Strean2Sea's Mask Prep Kit Defog and Scrub is the perfect solution for clear-vision underwater. The non-toxic, biodegradable, and reef-friendly formula is fast and easy to use; just apply Mask Scrub onto the lenses, rub then rinse. Defog is then applied to the inside surface of the mask lens with a few drops of water, polishing it to a streak-free finish. Non-abrasive and safe for glass and all types of goggles, the professional strength formula ensures optimal clarity for all your aquatic adventures.