The SHEATH 4.0 is our most athletic model to date, featuring a unique black and white SHEATH branded waistband, as well as a slightly longer leg, a luxurious 95% Modal and 5% Elastane fabric blend and our new Dual Pouch technology. In terms of isolation from the thigh region, the Dual Pouch is similar to that of our classic Zen Pouch. What sets it apart, however, is that our Dual Pouch achieves an even higher level of comfort for those truly stifling days, coming equipped with a circular seamed urination hole that allows for a gentle and unobtrusive separation between the penis and testicles. This model also features a quick access fly similar that of our SHEATH 3.21 Fly series. The sleek, stylish appearance and inexplicable comfort of the SHEATH 4.0 will truly change the way you think about your underwear.