The EagleEye-SL mask offers a large teardrop shaped single tempered glass lens to improve your peripheral and look-down vision. The inside of the SharpImage lenses have a yellow color tint that defines faint edges and increases depth perception. The outside of the lens has a silver 'mirror' coating which performs like sunglasses, reducing reflections and glare.Technical divers, cave divers and hunters diving in turbid waters will benefit from these lenses which help to optimize available light and improve visibility (very popular for spearfishing).