This is a set of 4 men's underwear tankinis. The size is F (M-L), which is the size at the time of purchase. They can be used not only by men but also unisex. I think it's "possible" to wear them as a group of four for a gag at events like wedding after-parties. There are various ways to use them, so please consider them. Please note that these are imported products, so please be aware of that.