one of the many types of different installation designs used to provide radiant heating for a variety of structures such as driveways , athletic fields and others is illustrated in fig1 and 2 . the design comprises a conventional wire mesh comprising intersecting wires 2 and 4 that are secured together at various intersections . the wire mesh is preferably laid over a bed of particulate material which , as illustrated in fig2 , comprises sand 6 but can comprise other types of particulate material such as pebbles , styrofoam , and other materials having similar characteristics . radiant heating tubing 8 is installed over the wire mesh . as illustrated in fig1 , the radiant heating tubing 8 has a plurality of straight sections and curved sections that extend in different directions . the radiant heating tubing 8 has an inlet 10 and an outlet 12 so that a heating fluid may be passed through the radiant heating tubing . it is understood that there will be many sections of radiant heating tubing 8 for an overall structure . the wires 2 and 4 forming the wire mesh typically have diameters of between about 0 . 156 and 0 . 500 inch and the radiant heating tubing may have diameters between about 0 . 375 and 0 . 875 inch . the present invention , however , may be used for restraining a far wider range of rigid member sizes . the construction of a prior art locking enclosure 20 ( improved in accordance with the invention as described below in connection with later fig6 - 10 ) is illustrated in fig3 - 4 . this prior art locking enclosure comprises first and second members 22 and 32 . the first member comprises a pivot portion 24 , a central body portion 26 preferably integral with the pivot portion 24 , a locking portion 28 preferably integral with the central body portion 26 , and an abutment portion 30 preferably integral with the central body portion 26 and extending outwardly therefrom . second member 32 comprises a pivot portion 34 , a central body portion 36 preferably integral with the pivot portion 34 , a locking portion 38 preferably integral with the central body portion 36 , and an abutment portion 40 preferably integral with the central body portion 36 and extending outwardly therefrom . members 22 and 32 have facing inner surfaces 52 and 54 and outer surfaces 56 and 58 and abutments 30 and 40 have respective abutment surfaces 60 and 62 . members 22 and 32 also include respectively abutments 48 and 50 positioned to move into an abutting relationship to limit the movement of the device 20 to a fully opened position . pivot portions 24 and 34 are joined by a living hinge 150 that extends between and is integral with pivot portions 24 and 34 . living hinge 150 may be combined with guide apparatus 152 comprising an arcuate groove 154 formed in the bottom surface 155 of the pivot portion 24 and an arcuate projection 156 formed on the top surface 157 of the pivot portion 34 and shaped correspondingly to the arcuate groove 154 to facilitate rotational movement therebetween . the arcuate groove 154 may be tapered as shown with a wide entrance portion 158 and a narrow end portion 160 and the arcuate projection 156 has a narrow entrance portion and a wide end portion 164 dimensioned to fit snuggly and move in groove 154 . when the device is in the fully closed position the wide end portion 164 of the arcuate projection 156 is located in the wide entrance portion 158 of the arcuate groove 154 and the narrow entrance portion 162 of the arcuate projection 156 is located in the narrow end portion 160 of the arcuate groove 154 . the dimensions of the arcuate groove 154 and the arcuate projection 156 are such that , when the device 148 is in the fully closed position , the arcuate projection 156 and the arcuate groove 154 are in a contiguous relationship . this together with the locking portions 28 and 38 helps enable the enclosure to become rigid in its locked position . these features are described in more detail in u . s . pat . no . 6 , 779 , 241 , col . 10 lines 30 - 60 , the disclosure of which is incorporated by reference . locking portion 28 includes a flexible arm 72 with an upwardly opening recess 70 . recess 70 in turn has a protruding strip 74 at its distal end projecting downwardly into the recess and locking portion 38 has a foot portion 78 that is contoured to cooperate with recess 70 when members 22 and 32 are in the closed position , as described in detail in u . s . pat . no . 6 , 779 , 241 at col . 6 line 63 to col . 7 line 19 , the disclosure of which is incorporated by reference . unfortunately , prior art locking enclosures as described above and illustrated in fig3 - 4 may inadvertently twist open . this is illustrated in fig5 a and 5b . thus , when a lateral force f is applied to member 32 while member 22 remains generally stationary , member 32 may twist away from member 22 as shown in fig5 a with a concomitant lateral bending at living hinge 150 . since the living hinge is not designed for such lateral movement , it may be permanently distorted impairing its intended functionality or it may tear if the lateral movement is too great . additionally , foot portion 78 of locking portion 38 will slide out of recess 70 generally laterally along with the twisting movement member 32 . if and when the foot portion 78 of locking portion 38 clears strip 74 of recess 70 , locking portions 28 and 38 will be fully released as shown in fig5 b . the present invention offers a unique modification to such prior art locking enclosures that prevents twisting relative movement between members 22 and 32 and hence both protects the living hinge from damage due to lateral movement between the members and prevents resulting inadvertent opening of the locking enclosure . turning now to fig6 , 6 a and 6 b , locking portion 28 of modified device 20 a comprises first and second members 22 and 32 joined by a living hinge 150 as described above in connection with prior art device 20 . in a preferred embodiment of this invention , members 22 and 32 are integrally molded using a plastic material such as a polyethylene , a nylon or another plastic material having similar characteristics including particularly the ability to form an integral living hinge between the two members . modified device 20 a has a flexible receptacle portion 72 having a recess 70 a formed therein , and the locking portion 38 on the second member comprises a foot portion 78 a configured to fit within the recess . the recess in the receptacle end includes a base surface 71 and an overhanging wall 69 at its distal end . the outer surface of overhanging wall 69 is radiused as shown to form a guide surface 76 . additionally , a guide protuberance 77 , preferably of a regular triangular in shape as shown in fig6 c , may be provided to help facilitate the engagement of the locking portions by directing the foot portion into alignment with the recess . preferably , a vertex of the triangular portion will be directed toward foot portion 78 a to best cooperate with bevels 87 , which are described below . a first guide in the form of a protruding strip 74 projects from the proximal overhanging wall 73 toward the base surface of the recess . a second guide in the form of a protruding strip portion 75 is located at the distal end of the recess and projects upwardly from base surface 71 toward the distal overhanging wall 69 . locking portion 38 in turn includes a foot portion 78 a with a bottom surface 79 configured to ride along guide surface 76 as locking portions 28 and 38 engage and foot portion 78 a enters recess 70 a in the receptacle portion . the leading or distal edge of the foot portion may include a beveled edge 81 which contacts the underside of overhanging wall 73 as locking portions 28 and 38 engage and foot portion 78 a enters recess 70 a . as best seen in fig6 c and 6d , a longitudinal slot 80 with a bottom 82 is formed in underside 79 of the foot and is located and dimensioned to pass over and receive guide protuberance 77 when foot portion 78 a is engaged in recess 70 a . foot portion 78 a also may include an entry 83 including a through - slot 85 extending from foot bottom surface 79 to the top of the foot . this through - slot is dimensioned to clear and engage strip portion 74 when the foot enters recess 70 a . additionally , the leading edge of the foot may include levels 87 angled inwardly toward slot 80 to facilitate the initial engagement of locking portions 28 and 38 , first guiding the foot over protuberance 77 and later guiding through - slot 85 over strip 74 . thus , as members 22 and 32 are moved toward a closed position , bevels 87 facilitate the engagement of foot portion 78 a with protuberance 77 as the underside 79 of foot portion 78 a rides over guide surface 76 causing arm 72 to flex downwardly . as foot portion 78 a moves into recess 70 a , the trailing end 91 of the foot clears the hook end 93 of distal overhanging wall 69 with strip 75 moving into slot 80 and flexible arm 72 moving back to its original position . the engagement of the slot with both the downwardly and the upwardly projecting strips ensures that the foot will be securely held in the recess in a manner that resists a release due to twisting in prior art devices , as illustrated in fig5 a or 5 b . this twisted release resistant configuration cooperates with living hinge 150 to produce a device which resists opening or destruction by twisting movement of locking enclosure device 20 a surprisingly well , as compared to prior art devices ( e . g ., that of fig3 and 4 ). furthermore , this twisted release resistant configuration additionally cooperates with guide apparatus 152 to further enhance the resistance of the device to opening or destruction by twisting movement . the movement of locking enclosure 20 a from an open position as illustrated in fig7 , to a closed position as illustrated in fig1 , may be controlled by a tool of the type illustrated in u . s . pat . nos . 4 , 801 , 061 and 5 , 350 , 267 which are incorporated herein in regard to the structure and operation of the tool by reference thereto . in such a tool , a plurality of locking enclosures 20 a in the opened position , illustrated in fig7 , are supported on a magazine and preferably resiliently urged toward the planar surface 92 of an end plate 90 . pivot portions 24 and 34 of the locking enclosure preferably have a total thickness that is slightly less than the thickness of the central body portions 26 and 36 , the locking portions 28 and 38 and the abutment portions 30 and 40 so that the facing surface of the foremost device 20 is compatible with the generally planar surface 92 . the movement of locking enclosure 20 from an open position to a closed position is illustrated in fig7 - 10 . in fig7 , the foremost device 20 a has been moved against the generally planar surface 92 . the tool has two spaced apart force applying plungers 126 and 128 having lower surfaces 130 and 132 located to contact a portion of the abutment surfaces 60 and 62 to apply an equal amount of force to the abutments 30 and 40 . as illustrated in fig7 , the portion 134 of the end plate 90 has been placed in contact with the portion 116 of a radiant heating tube 8 . as the plungers 126 and 128 begin to apply force , at least the control portion of the control surface 170 moves into contact with the first portion 102 and the control portion of the control edge 172 moves into contact with the first portion 96 to hold the pivotally connected members 22 and 32 in the opened position as the device 148 is moved downwardly over the generally planar surface 92 . as the force is continued to be applied , the foremost device 20 a is moved over the generally planar surface 92 with at least a control portion of the control surface 170 in contact with the second portion 102 and the control portion of the control edge 172 almost out of contact with the first portion 96 so that the end device 20 is ready to be moved into a partially closed position as illustrated in fig8 . guide surfaces 96 and 102 of guide 94 extend for a greater distance to insure that the device 20 remains in an opened position until the device has moved over the heating tube 8 and the wire 118 . as the foremost device 20 a continues to be moved downwardly over the generally planar surface 92 , the lower edges 174 of pivot portion 24 moves into contact with portion 116 to stop the downward movement of the foremost device 20 a . as the downward directed force is still being applied by the force applying plungers 126 and 128 , either the end plate 90 and therefore the tool is moved upwardly or the heating tube 8 and the portion 118 are moved downwardly away from the edge 134 . the locking portions 28 and 38 have been moved toward each other so that the foot portion 78 has moved into contact with the flexible arm 72 to begin to apply a force thereto and the heating tube 8 and the wire portion 118 are enclosed within the inner surfaces 52 and 54 of members 22 and 32 . the plungers 126 and 128 continue to apply a force to the abutments 30 and 40 to move the locking members 28 and 38 so that foot 78 a deflects the flexible arm 72 and snaps into the recess 70 a as the flexible arm 72 moves back to its original position as described above and illustrated in fig1 . although illustrated in fig1 , the area enclosed by the inner surfaces 52 and 54 is slightly greater than the area of the heating tube 8 and the wire portion 118 , a tighter fit may of course be achieved by shortening members 24 and 34 . all references , including publications , patent applications , and patents , cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein . the use of the terms “ a ” and “ an ” and “ the ” and similar referents in the context of describing the invention ( especially in the context of the following claims ) are to be construed to cover both the singular and the plural , unless otherwise indicated herein or clearly contradicted by context . recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range , unless otherwise indicated herein , and each separate value is incorporated into the specification as if it were individually recited herein . all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context . the use of any and all examples , or exemplary language ( e . g ., “ such as ”) provided herein , is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed . no language in the specification should be construed as indicating any non - claimed element as essential to the practice of the invention . preferred embodiments of this invention are described herein , including the best mode known to the inventors for carrying out the invention . it should be understood that the illustrated embodiments are exemplary only , and should not be taken as limiting the scope of the invention .