I read reviews of people saying that the polyamide is some nasty, irritating material.  Well, it's nylon.  It's very thin and the polyamide version is very stretchy (more than 20% spandex).  I love the feel of nylon and polyester; this is no exception.  These underwear give me a gross-looking flaccid mini-boner because of the way they hold my dick, but they are so comfortable.  Better than the Andrew Christian underwear I've been wearing.  The pouch lifts my balls up without squeezing them (thank you spandex).