Y-fronts refers to the style of men's underwear (usually briefs, and some boxer briefs) in which the opening is an inverted "Y" shape. It is the style of briefs sold by Jockey, and was the original form of tighty whities when they debuted back in the 1930s. Nowadays, it is more common for briefs to have a diagonal fly (and boxer briefs generally have diagonal flies), but this category is used for the traditional y-front shape. The fly of y-fronts is easier for men to use (to urinate out of) compared to the diagonal fly.