The M3 Mask provides distortion-free vision and a superior fit. The low-profile design uses a rigid frame and two lenses with UltraClear glass. The low iron content produces a higher light transmittance and a reduced green tint inherent in other glasses. This makes the lenses distortion free and helps improve color and visibility in low light conditions underwater. Optical lenses from -1.5 to -8.0 diopters available. Optical lenses available -Item code RX013 Frameless 100% pure silicon skirt Ultra-Clear lenses Easily fitted with optical lenses from -1.5 to -8.0 diopters Wide vision and low volume 4 way buckle design for superior comfort and storage if needed Please note there will be an additional 2 to 3 days processing time for most RX lenses Returns are not accepted for used lenes. Only unused lenses are eligible for return with store credit.