The multi-layer, red version of Smith’s standard Sensor Lens, the Red Sensor is good for low light conditions. The layered coating on this lens increases color definition and depth perception in varying degrees of flat light. The Red Sensor has a 60% VLT rating, and therefore does not work optimally in sunny conditions. VLT, or visible light transmission, refers to the amount of light from the visible spectrum that is allowed to pass through the goggle lens.