Promate RX Snorkeling Purge Mask with Prescription Lens Available for Snorkel Scuba Dive Nearsight corrective lens available from -1.0 to -10.0 by increments of 0.5/OP270 IF YOU NEED DIFFERENT CORRECTIVE LENSES ON EACH SIDE, PLEASE SEND US A MESSAGE WHEN PLACING YOUR ORDER. Two-window, slim and low profile snorkeling mask with Broad peripheral view. Easy adjust buckles attaching on skirt directly, which makes swivel function more flexible and may fits a wide range of face shapes. Soft and shaped dimples on both sides of nose pocket, which mask equalization easily.