Promate Farsightedness RX Prescription Snorkeling Mask with Farsight Optical Corrective Lens +1.0 to +4.0 Optical lenses available from +1.0 to +4.0 by increments of 0.5 (for far sighted)./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.