HEAD by Mares Marlin Purge Mask and Dry Snorkel Combo (Black) EXCLUSIVE SOFT TOUCH SILICONE BUCKLES- for an easy strap adjustment. The buckles are fixed on the skirt instead of the frame, for increased comfort. SILICONE COMFORT-BITE- Hypoallergenic Silicone mouthpiece with "comfort-bite" design prevents jaw fatigue. EASY EXHALE- purge valve to keep tube clear of water. SILITER FLEX-Pre-curved flex tube provides comfort during use. SNORKEL KEEPER- Low profile, swiveling snorkel keeper is comfortable against the face. Unique design reduces pull on mask strap, compared to non-swivel versions, and lessens snorkel drag through water.