Axolom STP Jockstrap is a soft Breathable Cotton STP Packing underwear. The packing underwear features an anti-roll middle “O Layer”. The button fly underwear is made for packing STP packer  (It can be soft packers or Stand to Pee Prosthetics). Now STP Packer can be used without a harness. Synonyms: STP Jockstrap Button-Fly Underwear, STP Brief, FTM STP Packing Jockstrap, FTM Jockstrap. Introduction:  The Axolom STP Jockstrap underwear has two layers. The outside layer shows two buttons that allow a person to STP (Stand to pee) in front of public toilets or private spaces through an FTM STP Packer. The inside layer(O Layer) keeps your STP attached to your body. It also has a layer of keeping scrotum. The STP Jockstrap Underwear works for specially Thinker, Handy. It also works for other STP packers as well. Some STP packers may not suitable for it. Size Chart:  S (29” - 32”),  M (33” - 35”),  L (36” - 38”),  XL (39” - 41”),  1XL (42” - 45”),  2XL (46” - 49”),  3XL (52” - 55”). AXOLOM STP jockstrap harness work with most of our STPs, which have a shaft diameter of less than 1.5". ( DOES NOT fit the Homerun, Hoodie)   Material: 95% Cotton, 5% Spandex. Colour: Black, Navy Blue Wash Cold, Tumble Dry or Medium Low. -Wide comfortable waistband, with the underwear itself made from high-quality fabric to last wash after wash -Button fly opening to easily access the shaft -Soft fabric-covered O ring to keep the shaft of your packer/STP in the natural hang position.  -Interior elastic loop harness, hold your STP secure and in a natural position. ( Can be cut off if you think it's unnecessary.)