You know the size "OSFM" - "One Size Fits Most", right? Well, you and I are clearly not "most" people. Simple things like an ill-fitting $10 or free swim cap can spoil an otherwise great little swim workout. This moulded swim cap is super stretchy and can accommodate a big head or big hair and ponytails. Now you can keep your hair covered, keep your head in the game and focus on the work.