This is the RX Prescription Lenses for Cressi Sub Focus Mask Lens - Optical Lens ONLYFeatures: Prescription mask available - Item code: MSK138 Please note there will be an additional 2 to 3 days processing time for most RX lenses Cost is per single lens only If you are ordering these with a mask and want us to install them, please email us after you place your order with which lens goes in which eye Fits: Cressi Focus Mask Easy to Install Range: -1.0 to -8.0-Diopter Increments: 0.5 Increase Your Vision Enjoy Diving More! Tempered Glass Lenses are made of tempered glass and are available from -1.0 to -8.0 in 0.5 Diopter increments. Returns are not accepted for used lens. Only unused lens are eligible for return with store credit.