referring now to fig1 the new and improved flexible transition connector , generally referred to by reference numeral 10 , is shown in an illustrative and common end use application . more particularly , an overhead wiring duct 12 mounted on a planar horizontal ceiling panel 14 is shown extending adjacent a vertically extending planar wall panel 16 . a junction box 18 is shown mounted to wall panel 16 . a lead - in duct projection 20 extends upwardly from top wall 22 of junction box 18 . as shown in fig1 wiring duct 12 and duct projection 20 are four - sided structures and in the preferred embodiment depicted therein each has a generally square cross - sectional configuration . the relative orientation of overhead duct 12 with respect to the junction box lead - in 20 requires that the longitudinal axes of a plurality of wires or cables extending within wiring duct 12 be redirected through substantially a 90 ° angle before entering lead - in duct projection 20 . in accordance with the invention , a gradually curving or bended connection may be made using preferred connector 10 . the flexible transition connector 10 , in the preferred embodiment shown in fig1 and 2 , includes a length of generally cylindrical flexible tubing 24 having a pair of opposed ends 26 , 28 . flexible tubing 24 is preferably flexible convoluted tubing having a longitudinally extending axial slit 30 extending the length thereof . tubing 24 is thereby provided with a resilient generally c - shaped configuration . flexible convoluted tubing 24 is defined by a continuous peripheral sidewall having an inner facing surface 32 defined by a plurality of spaced apart ribs 34 alternating with a plurality of spaced apart grooves 36 as is best shown in fig7 . tubing 24 includes an interior space 38 accessible through slit 30 adapted to receive a plurality cf wires or cables in loose or bundled form . connector 10 also includes a pair of substantially identical duct transition converters 40 affixed to ends 26 and 28 of flexible tubing 24 . in the preferred embodiment , connector 10 further includes a pair of substantially similar cinch or adjustable hose clamps 42 and a bundle tie 44 . further details of the structure and operation of flexible transition connector 10 will be more particularly set forth hereinafter . in greater detail and referring now to fig1 - 7 , the new and improved duct transition converter 40 comprises an elongate generally tubular converter body including a first end 48 , an opposed second end 50 and an intermediate transition section 52 extending therebetween . the cross - sectional configuration of converter body 46 varies along its length such that the first end 48 has a square cross - sectional configuration and the second end 50 has a circular cross - sectional configuration . the transition section 52 changes from square to round along its length in such manner that transition section 52 may be characterized as being frusto - conical in nature . first end 48 includes a resilient cuff portion 54 for making clamping engagement about a multi - sided end of a wiring duct , such as wiring duct 12 or duct projection 20 . second end 50 includes an elongate cylindrical sleeve portion 56 . a plurality of radially spaced - apart vanes 58 project outwardly from the circumference of sleeve portion 56 . converter body 46 defines an internal passageway 60 for receiving a plurality of wires or cables . an axially extending side slit or slot opening 62 is disposed along the length of converter body 46 to provide lateral access to passageway 60 to permit wires or cables to be added to or removed from passageway 60 in use . slot opening 62 defines a pair of elongate opposing edge surfaces 64 and 66 in converter body 46 . converter body 46 has a resilient , generally c - shaped cross - sectional configuration , permitting opposing edge surfaces 64 and 66 to be elastically flexed toward or away from each other in the direction of arrow , a , shown in fig3 - 4 . referring to fig4 - 5 , a shoulder 68 defining a forward stop surface 70 is provided in interior passageway 60 between cuff portion 54 and transition section 52 opposite slot opening 62 . in the preferred embodiment shown in fig1 - 7 , converter body 46 is a unitary or one piece body , molded from a suitable thermoplastic molding composition . illustrative thermoplastics may include thermoplastic polyesters , polyamides , such as nylons , polycarbonates , polyolefins such as polyethylenes , polypropylenes , polyvinyl chloride and the like . flame retardant compositions of these thermoplastics having a 94 vo rating are preferred . an especially preferred thermoplastic molding composition is a 94 vo flame retardant polyvinyl chloride composition . thermoplastic molding compositions are abundantly commercially available from several sources . referring now to fig7 a duct transition converter 40 is shown in a fully mated condition connecting a square end of a wiring duct , such as duct 12 or 20 , to one end of flexible convoluted tubing 24 . in the preferred embodiment depicted therein , sleeve portion 56 adjacent second end 50 of converter body 46 is telescopingly received through tubing end 26 so that it extends within the interior space 38 in tubing 24 . as shown in fig6 sleeve portion 56 is provided with an inner diameter , dimension b , which is equal to or slightly greater than the internal diameter , dimension c , of interior space 38 , defined between aligned and opposed surfaces of ribs 34 . also referring to fig6 - 7 , sleeve portion 56 is also provided with a second internal diameter , dimension d , defined by the separation distance between aligned and opposing surfaces of grooves 36 . the difference between flexible tubing 24 dimensions c and d is shown as dimension e , which generally defines a length dimension to recessed areas along inner surface 32 defined by grooves 36 . these same recesses have an associated width dimension , shown as dimension f , and defined between adjacent parallel radially - extending surfaces defining a groove 36 . in accordance with the preferred embodiment , sleeve portion 56 is provided with vanes 58 . vanes 58 extend normally outwardly from an outer surface of sleeve portion 56 to a height dimension , shown as dimension g in fig5 which is approximately equal to dimension e of flexible tubing 24 . vanes 58 also have a width or thickness dimension h , shown in fig3 which is equal to or slightly greater than the width dimension , f , of grooves 36 . as a result of its construction and dimensions , it is necessary to inwardly resiliently compress sleeve portion 56 of converter body 46 by moving elongate slot edge surfaces 64 and 66 toward each other so that vanes 58 can clear the surfaces of ribs 34 defined in inner facing surface 32 of flexible tubing or conduit 24 . the second end 50 of converter body 46 is inserted until the end 26 of tubing 24 overlays substantially the entire length of sleeve portion 56 , as shown in fig7 . thereafter , when compressive forces on the converter body 46 are released , sleeve portion 56 resiles outwardly and edges 64 and 66 move apart to return the sleeve to its original dimension b . consequently , the outer surfaces of sleeve portion 56 biasingly engage the surfaces of rib portions 34 defined in the inner surface 32 of tubing 24 . this action tends to cause an outward flexing of tube end 26 , which by virtue of the resilient construction of tubing 24 , in turn causes the tube end 26 to exert a balanced resilient circumferentially inwardly directed compressive force against the sleeve portion 56 . accordingly , the resilient construction of sleeve portion 56 and flexible tubing 24 provide a cooperative , enhanced frictional biased engagement of the sleeve 56 within tube end 26 increasing the withdrawal force required to separate the converter body 46 from tubing 24 . moreover , when sleeve portion 56 is compressed , inserted into tubing end 26 and released , the resilient expansion of sleeve portion 56 causes the vanes 58 to penetratingly enter and become engaged in an aligned groove 36 in tubing surface 32 . engagement of vanes 58 in a groove 36 effectively limits axial displacement of the tubing end 26 with respect to the sleeve portion 56 in its inserted condition . in addition , because vanes 58 are provided with a thickness dimension h which is equal to or slightly greater than the width dimension f of the groove 36 , penetrating engagement of the vanes 58 into groove 36 causes an outward flexing force to be exerted against the radial sidewalls defining groove 36 . again , because of the resilient nature of flexible tubing 24 , resilient balanced inwardly directed compressive or pinching forces are exerted by the groove surfaces against the vane surfaces . this cooperative engagement of the vanes 58 within the groove 36 provides an enhanced strain relief effect because a larger force is required to dislodge vanes 58 from the groove 36 than would be required in the absence of these developed gripping forces . a further guarantee that the sleeve portion 56 and tubing end 26 will remain affixed to one another in use even under heavy withdrawal force shocks or loading may be provided as shown in fig7 by applying a circumferential tie or clamp 42 after installation of the sleeve portion within tubing end 26 , adjacent end 26 and positioned at a point along sleeve portion 56 intermediate vanes 58 and the junction of the sleeve portion 56 with the transition portion 52 of the converter body 46 . the clamp or tie 42 effectively prevents end portions of axial tubing slit 30 from opening up in a manner which would allow converter body 46 to be disengaged from the tubing 24 . clamp 42 cooperates with engaged vanes 58 to limit axial displacement of the converter 40 from the tubing end 26 . referring now to the left hand portion of fig7 duct transition converter 40 may be connected to the end of a multi - sided wiring duct , such as ducts 12 or 20 , by pushing the first end 48 onto the duct end until a leading edge of the duct end engages the forward - stop surface 70 defined by shoulder 68 . the duct end is thereby telescopically received within cuff portion 54 . cuff portion 54 has a square cross - sectional configuration , as shown in fig4 having interior side dimensions , i , which is selected to be equal to or slightly less than the corresponding side dimension j of the square duct end 12 or 20 , as shown in fig7 . installation of the cuff portion 54 over the duct end causes an outward flexing of the cuff portion 54 wherein the edge surfaces 64 and 66 along cuff portion 54 tend to be spread apart . the resilient configuration of the converter body 46 causes balanced resilient compressive forces to be developed by the surfaces of the cuff portion 54 against the outer surfaces of the duct end . cooperative biased engagement and enhanced frictional gripping of the duct end is thereby provided . the depth of insertion of the duct end within cuff portion 54 dictated by the positioning of shoulder 68 with respect to first end 48 of converter body 46 is selected to provide a length of overlapping gripping engagement which is sufficient or effective to ensure that only by applying a significant axially directed withdrawal force on the cuff portion , can converter 40 be unmated or dislodged from the duct end . moreover , the shoulder 68 positioned opposite the slot opening 62 acts as a stiffening gusset which further enhances the resilient gripping response of the cuff portion in use . the new and improved duct transition converter 40 is also designed so that the duct engagement provided at either the first end 48 or the second end 50 tends to enhance the duct engagement of the opposed end of the converter 40 . more particularly , outward flexing of the converter body 46 caused by inserting the cuff portion 54 onto a duct end , causes the outward resilient engagement of the sleeve portion 56 against the tubing end 26 to be increased . inward compression of the sleeve portion 56 at the second end 50 of converter body 46 , caused by installation of the sleeve portion within the tubing end 26 and by tightening the circumferential grip of cinch clamp 42 act in favor of the inward resilient gripping engagement of the cuff portion 54 at first end 48 against the duct end . referring again now to fig1 - 2 , new and improved universal transition connectors 10 incorporate the new and improved duct transition converters 40 of this invention to provide a means for connecting the ends of spaced apart wiring duct elements in a gradually curving manner . connector 10 may be provided in pre - assembled form or as a kit of parts to be assembled in the field . as shown in fig2 connector 10 includes : a length of flexible tubing which is preferably of a flexible convoluted tubing type , such as tubing 24 . the flexible tubing 24 should comprise a resilient thermoplastic material which is preferably rendered flame retardant . a preferred flexible convoluted tubing is a 94 vo flame retardant grade of polypropylene . flexible tubing or conduit suitable for use in connector 10 is generally available from a number of commercial sources . connector 10 further includes a pair of duct transition converters 40 as described above and preferably includes a pair of cinch clamps 42 installed as described in connection with fig7 above . generally , the cinch tie or clamp 42 may comprise any tensionable looping strap assembly adapted to circumferentially engage the mated sleeve portion and tubing end of the connector . suitable items for use as adjustable hose clamps 42 include cable clamp and cable tie products used in the wiring industry . they may be of the one - piece , two piece or three piece types and may be permanent after tensioning or can be of the releasable locking type . if permanent ties are used , the strap may need to be cut for access and a new substitute tie added to re - form the connector 10 if changes in the wiring or cables are needed . preferably , the clamps 42 are of a releasable , reusable type to avoid waste . an especially preferred clamp for use as clamps 42 is a snapper ® brand adjustable hose clamp available commercially from tyton corporation . other suitable products for use as clamps 42 will readily suggest themselves to those skilled in this art . as shown in fig1 - 2 , connector 10 additionally includes a bundle or cable tie 44 positioned over flexible tubing 24 at a point intermediate the length thereof . cable ties 44 for use herein are well known and may be the same as or different from the adjustable hose clamp 42 . one or more cable ties 44 may positioned at various locations along the length of tubing 24 . the purpose of cable tie 44 is to prevent the axial slit 30 from opening up in use or buckling open during bending of the connector 10 along the length of tubing 24 . in accordance with the invention , connectors 10 are provided with access openings including axial slit 30 in flexible tubing 24 and slot openings 62 in each of converters 40 . when the hose clamps 42 are in a loosened condition , the sleeve portions 56 may be rotated within tubing ends 26 and 28 until each slot opening 62 is aligned with the slit 30 at each end of tubing 24 . in this aligned condition , continuous lateral access to the interior wire or cable receiving space 38 and passageways 60 along the entire length of connector 10 is provided enabling wires or cables to be removed , added or replaced from the connector 10 and the overall installation without the need for complete disassembly . connector 10 provides a connector for making curved transition connections between duct members along six axes of change in a single connector making it universally useful for all or most duct interconnection applications . referring now to fig8 - 11 , an alternate duct transition converter 80 in accordance with the present invention is shown . as shown in fig8 duct transition converter body 80 comprises a converter body 82 including a pair of substantially identical , selectively releasable interlocking hermaphroditic housing halves 84 , 84 . in assembled form , converter body 80 is similar in most respects to converter body 46 with certain exceptions . converter body 82 includes a first end 88 defining a cuff portion 90 having a generally square cross - sectional configuration adapted to telescopically receive and grippingly engage the square end of a wiring duct , such as ducts 12 or 20 . converter body 82 also includes a second end 92 including an elongate sleeve portion 94 . instead of having an elongate tapered frusto - conical transition section , converter body 82 has a stepped outer configuration as shown in fig9 - 10 . the transition from a square to round configuration is defined in converter body 46 by an inner upstanding partition wall 96 . a parallel end wall 98 extends inwardly adjacent second end 92 . the hermaphroditic housing design of converter body 82 bisects body 82 lengthwise forming a pair of parallel spaced apart elongate edge surfaces 100 and 102 extending along the top of the open side of each housing half 84 , 84 . in accordance with this embodiment , each housing half 84 is provided with complimentary releasableinterlocking features for securing the pair of housing halves 84 in mated or assembled condition . more particularly , each housing half 84 includes a pair of perpendicular side panels 104 and 106 adjacent first end 88 for forming cuff portion 90 . a generally rectangular resilient tab 108 having a centrally disposed lock aperture 110 extends perpendicularly from edge surface 100 of housing half 84 at a point intermediate cuff portion side panel 104 . on the exterior surface of the opposing panel 106 there is provided a rectangular recess 112 having a thin rectangular lock projection 114 generally centered with respect to the length of recess 112 and extending from elongate edge surface 102 to a point intermediate the width of recess 112 . tab projection 108 is resiliently deflectable , being cantilevered from side panel 104 . accordingly , as two housing halves 84 are brought together so that their elongate edge surfaces 100 and 102 are advanced into abutting surface to surface engagement , the elongate edge surface 100 on a first housing half 84 lies adjacent edge surface 102 on the complimentary housing half 84 . advancing the housing parts together causes tab projection 108 to be deflected outwardly to slide over the outer or top surface of lock projection 114 until the tab edge 116 defined by aperture 110 clears the engaging edge 118 of lock projection 114 . at this point , the tab projection 108 is free to reside inwardly to assume a flush condition within recess 112 with respect to the outer surface of complimentary side panel 106 as shown in fig1 . in this mated condition , tab edge 116 is engaged on engaging edge 118 in a manner which prevents the housing halves 84 from being separated from each other in use . as shown in fig1 , tab recess 112 is provided with sufficient excess width to leave a clearance or tool - receiving gap 120 for receiving a tool , such as a screw driver or the like , to lift the tab projection 108 out of engaged or locked position with respect to lock projection 114 , in order to separate the housing halves 84 to provide access to cables or wires disposed in the interior space defined by the assembled converter body 82 . as shown in fig8 - 11 , the sleeve forming portion of elongate edge surfaces 100 and 102 are provided with an upstanding lip 122 and a shoulder recess 124 , respectively , which cooperate to form an aligning and frictionally engaging lap joint in the sleeve portion 94 of assembled converter body 82 . each of the upstanding walls within housing half 84 , namely partition wall 96 and end wall 98 , are provided with semi - circular or concave recesses or cut - outs 126 and 128 , respectively . cut outs 126 and 128 form a pair of sleeve - engaging circumferential clamping sections in the assembled converter body 82 . more particularly , the end of a flexible convoluted tubing such as tubing 24 is laid within the sleeve forming portion 94 of housing half 84 . the outer surface of flexible convoluted tubing 24 includes a plurality of spaced apart indentations 130 , shown in fig7 corresponding to ribs 34 defined along the inner facing surface 32 of tubing 24 . the tubing 24 can be pressingly engaged into housing half 84 so than an indentation 130 is forced onto and grippingly engages each of cut outs 126 and 128 . thereafter , when the complimentary housing half 84 is mated to the first housing half 84 , its cut outs 126 and 128 are grippingly engaged in the opposite sides of the indentations 130 . in this manner an end of flexible tubing 24 is telescopically received and affixed within the sleeve portion 94 of converter body 82 . after the flexible tubing is affixed into the sleeve portion 94 and housing halves 84 has been matingly engaged to form the converter body 82 , the cuff portion 90 may be press - fit over the end of a wiring duct , such as 12 or 20 , to form the duct connection . referring now to fig1 - 17 , another hermaphroditic duct converter 150 is shown . converter 150 is similar in most respects to duct converter 80 shown in fig8 - 11 , with the exception that its sleeve - forming sections 152 , also includes releasable interlocking features in addition to the tab 108 and lock projection 114 disposed in the cuff forming portion 154 . more particularly , as shown in fig1 - 17 , each hermaphroditic housing half includes an elongate upwardly projecting latch arm 156 having a free end 158 with an outwardly projecting cantilevered locking barb 160 . latch arm 154 extends above an elongate edge surface 100 at a point intermediate the length of sleeve forming portion 152 . a complimentary latch window 162 is disposed through an opposing side wall portion of sleeve forming section 152 , spaced downwardly from the opposite elongate edge surface 102 . a latch guide recess 164 is defined along the inner surface of sleeve forming portion 152 extending between latch window 162 and elongate edge surface 102 . guide recess 164 thereby defines a reduced thickness sidewall portion 166 extending between elongate edge surface 102 and latch window 162 , and defines a latch engaging surface 168 at window 162 . locking barb 160 forms a latch shoulder 170 and is provided with an angled cam surface 172 . cam surface 172 causes inward deflection of latch arm 156 as it engages the upper end of sidewall portion 166 when the housing halves are brought together to their assembled condition . latch barb 160 slides within latch guide recess 164 until it clears latch window 162 . latch arm 156 then resiles outwardly causing latch shoulder 170 to lockingly engage surface 168 . latch barb 160 can be inwardly deflected by a tool to release the latch arm 156 from the latch window 162 to disengage the hermaphroditic housing halves from their mated condition . although the present invention has been described with reference to certain preferred embodiments , modifications or changes may be made therein by those skilled in this art without departing from the scope and spirit of this invention as defined in the appended claims .