classic goggles with otg system . the sinner batawa otg comes with a classic design and a wide field of vision. thanks to the otg system, you can wear your prescription glasses under these goggles. the sinner batawa otg fits perfectly with your helmet as it is equipped with an adjustable and non-slip strap.full red mirror lensthis lens is perfect for sunny and slightly cloudy days on the mountain.transmittance of visible light: 8-18 %