This harness is made to keep your Form Function STP in the perfect place and ready for use at all times. Made with thick and plush high quality elastic the Soft Slingshot is completely washer and dryer safe.With no waist band- this harness stays in place with two elastic thigh straps. The elastic has a great stretch and is designed to fit snuggly.   See sizing guides below.  Please note this harness is designed to work with the Model D, Model A, Model E and Sport STPs. Some folks use it with soft packers (or other StPs) as well, but we cannot promise this will be a good fit with anything but the StPs listed above we not are responsible for any damage to packers or STPs that are not made by Form Function. Also note that these are extremely popular and handmade and sometimes we run out of them before our system can update the stock level. We appreciate your understanding if you have to wait a few more days for yours to ship STP NOT INCLUDED