referring now to the drawings , and especially to fig1 a tennis ball holder generally indicated by numeral 10 is shown therein mounted on a belt 12 , with a tennis ball 14 held in holder 10 . the ball holder 10 generally consists of two main portions , an injection - molded plastic base 16 and an injection - molded plastic retaining ring 18 . in this instance , plastic for each of the parts is acetal resin ; and specifically , delrin 500 manufactured by e . i . dupont de nemours & amp ; co . the base 16 , as was mentioned above , is an injection - molded part . the base has a cavity defining a portion of a sphere less than a hemisphere . the base has a body 20 which generally has a substantially uniform thickness . a base connector tongue 22 is formed integral with one edge of the body 20 . base connector tongue 22 extends tangentially from base 16 . base connector tongue 22 is substantially flat . the base connector tongue 22 includes an aperture 24 . base connector tongue 22 forms one portion of a ball holder connector 25 . a pair of fingers 26 and 28 are formed integral with body 20 of base 16 . referring now to fig3 aperture 24 has a pair of inwardly curving sides 30 and 31 . a support rib 32 is positioned adjacent aperture 24 . a support rib 33 is positioned adjacent aperture 24 and opposite support rib 32 . inwardly curving sides 30 and 31 have approximately 90 ° of curvature . inwardly curving side 31 is also a cam surface . a base connector bar 34 is formed integral with and perpendicular to support ribs 32 and 33 . base connector bar 34 is shaped like a comma . base connector bar 34 has a flat face 36 formed immediately adjacent cam surface 31 . a rounded face 38 is formed immediately adjacent flat face 36 . rounded face 38 has approximately 75 ° of curvature . a flat tab shoulder 40 is formed perpendicular to an edge of curved face 38 . a bottom face 42 is formed immediately adjacent tab shoulder 40 . bottom face 42 has curvature substantially parallel to that of curved face 38 . base connector bar 34 is widest at tab shoulder 40 and tapers to a line where cam surface 31 and bottom face 42 meet . a retaining ring tongue 44 is formed integral with retaining ring 18 . retaining ring tongue 44 has an aperture 46 formed therein . aperture 46 is bounded by a pair of tapered curving legs 48 and 50 . legs 48 and 50 are formed integral with retaining ring 18 and are curved approximately 75 °. retaining ring tongue 44 forms another portion of ball holder connector 25 . a tapered shelf 52 is formed integral with and perpendicular to legs 48 and 50 opposite retaining ring 18 . a hook 54 is formed integral with shelf 52 . hook 54 has a tapered leg 56 and a tapered lip 58 . leg 56 has a pair of tapering sides 60 and 62 . sides 60 and 62 have approximately a 15 ° taper . lip 58 has a pair of tapering sides 64 and 66 . sides 64 and 66 likewise have approximately a 15 ° taper . sides 64 and 66 end in a flat lip face 68 . side 60 and side 64 are perpendicular to each other and meet at a line 70 . sides 62 and 66 are also perpendicular to each other but meet in a curved fillet 72 . a hook stop 74 is formed integral with a portion of shelf 52 adjacent leg 56 of hook 54 and opposite aperture 46 . a hook shoulder 76 having a curved edge 78 is formed immediately adjacent leg 56 of hook 54 and opposite hook stop 74 . a rectangular tab 80 is formed integral with a side of aperture 46 opposite hook shoulder 76 . tab 80 is positioned approximately parallel to the side 66 of lip 58 . a tab reinforcement 82 is formed integral with tab 80 opposite aperture 48 . referring now to fig4 and 6 , base connector tongue 22 is positioned in operative engagement with retaining ring tongue 44 . in order to connect the two tongues together , tab 80 is first positioned against tab shoulder 40 . hook lip 58 is then rotated into contact with flat face 36 of base connector bar 42 . torque is then applied to retaining ring 18 to force lip face 68 of hook lip 58 along flat face 36 and cam surface 31 while bringing tab 80 into full engagement with tab shoulder 38 . leg 56 of hook 54 is resiliently forced back as hook 54 follows cam surface 31 . legs 48 and 50 also flex as an edge of lip face 68 rides over cam surface 31 of connector bar 42 . tab reinforcement 82 provides compressional support for tab 80 as it is forced against tab shoulder 38 . aperture 46 allows easier flexure of legs 48 and 50 as base connector tongue 22 and retaining ring tongue 44 are being snapped together . when hook lip 58 clears cam surface 31 , hook 54 snaps resiliently into engagement with connector bar 34 . tab 80 is abutted against tab shoulder 40 when base connector tongue 22 is fully engaged by retaining ring tongue 44 . legs 48 and 50 of retaining ring tongue 44 are mateably engaged by curved side 38 and flat face 36 of connector bar 34 . lip side 64 of hook 54 is snapped into engagement with bottom face 42 of connector tongue 22 . leg 56 of hook 54 is held in tensile stress by base connector bar 34 . hook stop 74 is in contact with inwardly curving side 30 of aperture 24 to hold hook lip 58 against bottom face 42 . when a force is applied to retaining ring 18 tending to move it away from face 38 , a corresponding torque is transmitted through retaining ring tongue 44 to cause the tensile stress in hook leg 56 and lip 58 to increase and thereby to engage more forceably base connector bar 34 . in a similar fashion , if a force directed toward base 16 is applied to retaining ring 18 , tab 80 is forced into greater compressional engagement with tab shoulder 40 of base connector bar 42 . support ribs 32 and 33 prevent flexure of base connector tongue 24 when a force is applied to retaining ring 18 . thus , when stressed , retaining ring connector tongue 44 more forceably engages base connector tongue 22 . it may be appreciated that the construction of the base connector tongue may be formed integral with the retaining ring and that the construction of the retaining ring tongue may be formed integral with the base , thus reversing the positions of the two tongues . it may also be appreciated that the retaining ring may be easily snap - connected to the base by following the procedure herein above described . it may be also appreciated that visual inspection will disclose when the two tongues are in proper engagement . although a specific embodiment of the present invention has been shown and described in detail above , it is readily apparent that those skilled in the art may make various modifications and changes in the subject invention without departing from the spirit and scope of the present invention . it is to be expressly understood that the instant invention is limited only by the appended claims .