The HEAD Tarpon/Barracuda/Volo One Snorkel Set features a two-window mask with soft touch” silicone buckle technology, Volo Power open-heel fins with quick release buckles and designed with a channel thrust to maximize propulsion through the water. Also features a submersible dry top snorkel with comfort-bite mouthpiece and built-in whistle. Includes a reusable bag.Small/Medium fits shoe size US 3 1/2 - 6Medium/Large fits shoe size US 6 1/2 - 9Large/X-Large fits shoe size US 9 1/2 - 12