FTM STP Boxers for a Harness-Free Stand-to-Pee Experience. Cake Bandit STP Packing Trunks are made with super soft, breathable cotton. They can be worn with a foam insert, regular soft packer, or stand-to-pee device without needing a harness or packer strap.  This STP Packing underwear was designed to work with the STP Freely but may be compatible with other STP and packer models.   DETAILS Constructions Details: Our STP underwear has a 3-layer construction. The outside layer has buttons on the front to pull the STP through to pee. The middle layer has an opening to pull the shaft through the front. And finally, the inside layer (the one closest to your body) allows you to put the STP into the underwear and the shaft through to the second layer. 92% Cotton 8% Spandex Wash cold with like colors - will shrink a little in a hot or warm wash No Bleach Tumble Dry on Medium Low - will shrink a little in the dryer SIZING Small: 27"- 31”Medium: 32”- 35”Large: 36” - 38”XL: 39” - 42”2XL: 43”- 46"3XL: 47"- 52”