ADVANCED ANTI-FOG TECHNOLOGY- Built in proprietary Anti-Fog Films prevent fogging in all circumstances - easily replaceable anti-fog films for longterm fog-free use This High-quality diving and snorkeling mask is designed to provide unparalleled comfort and a perfect seal that won't leak. With its high-quality silicone skirt and two-way adjustable strap, the Tidal Mask ensures that you can enjoy your underwater adventures without any discomfort or fogging. Equipped with the ultimate advanced anti-fog technology, your Tidal Mask will remain fog-free for 6 months - 1 year, as long as you clean and maintain your mask after every use. Replacement anti-fog films are available to purchase.