Each 2-pack contains 2 size #17 xact-fit™ rings. the incredibly popular playzone has proven our revolutionary xact-fit™ 2.5mm (0.1") incremental cock ring sizing system is the most precise on the market. super strong, but soft to the touch, xact-fit™ rings stretch just enough to get on and off, but otherwise should provide a very comfortable (no pulled pubes!) And effective fit. the sizing # references the id in inches (#10 = 1.0" id, #11=1.1" id etc)all 14 xact-fit™ rings sizes are now available in single size 2-packs. 3 ring kits of m, l, xl and mixed are also available.don't know your size? We recommend you start with the play zone kit, which features 9 incrementally sized xact-fit™ rings on a bright orange mini traffic cone.each xact-fit ring is stamped with its size so no more guessing! Stack the rings for additional fun.the xact-fit set of penis rings are made from premium silicon with an advanced molding technique that provides a strong ring that will hold up to repeated stretching. the surface has been finished to reduce uncomfortable friction.xact-fit rings come in 14 sizes with a 0.1” (2.5mm) interval in between. they start at 1" in diameter and go up to 2.3". refer to our sizing chart to determine your fit. or try our play zone pack with 10 different sized rings to try different combinations!these Cock rings provide a firm grip, enough to retain blood in the penis. stretching to 2x their diameter, they can be looped around the base of the penis and underneath the scrotum, or use alone along the penis shaft or around the scrotum itself.