Promate Scuba Dive Mask Frameless Snorkeling Freediving Flexible Silicone for Leak-Proof, Comfort Seal: Skirt and strap come in soft, supple silicone, which molds to the shape of your face for comfortable fit and watertight seal. No more leaks or discomfort. Tempered-Glass Lens for Safety: Forget flimsy plastic lenses! This one is quality tempered glass, which resists scratching and shattering. Convenient Buckle for Easy Adjustment: Simply pull the straps to desired fit and the buckle will hold the straps securely in place. Presto: customized comfort. Rugged Enough for Scuba Diving: Thanks to its sturdy construction, your mask can stand up to all kinds of wear - from snorkeling in the pool to deep-sea scuba diving. One-Piece Lens: A snorkel mask should help you see better, not obstruct part of your view. Now you can enjoy all the underwater scenery clearly.