The Perla Mask is particularly suitable for Free Diving and Snorkeling, but just as appropriate for use in Scuba Diving. The Perla has Two Tempered Glass Lenses with a 100% High Quality Silicone Rubber Double-Feathered Edge Skirt for a great Seal on the Face, and will adapt to most people #39;s faces. The Perla is a Low Volume Mask that is Easy to Clear. Mask Cressi Perla : -For free and scuba diving and snorkeling -Accommodates most people faces -Tempered glass lens for extra durability -Low volume design makes it easy to clear -Wide field of view