Cressi BONETE Combo, Mask Snorkel Adult Snorkeling Gear Quality Since 1946 The mask skirt is made in 100% high quality silicone. Easy to asjust the lenght of the strap thanks to the adjustable buckles. Mask lenses in tempered glass. The snorkel features a splash guard on the top and a purge valve at the bottom. Comfortable mouthpiece made in silicone for reduce the jaw fatigue.