I am thinking that the sizes of these relate to the holding device, not the cup itself. Most of the molded plastic cups made in the US come in up to 3 sizes-youth, teen (to accommodate puberty changes) and adult. In my experience any adult cup sold as S,M,L,XL will have the same size cup, just larger shorts. If you want a better fitting cup you just about have to shop around for a different brand. I have never seen any size indicator on the cups themselves. It was stated in another post that just about all of these steel cups are molded in the same mold. If that is the case, a larger dude could be screwed.