Prizm Persimmon is an optimum lens for heavily overcast and snowy days. The tint enhances contrast and increases depth perception, helping you to see terrain easier in poor weather. Goggle Fit: Flight Tracker M only Lens Shape: ToricVLT: 39% (CAT 2)Visual Light TransmissionVLT, refers to the amount of light that penetrates a lens. A low percentage means less light passes through and a higher percentage lets an increased amount of light through. A lens with a lower VLT rating is better for bright conditions, where as one with a higher VLT is more suited for overcast and snowy days.TechnologyPrizm technology blocks specific wavelengths of light whilst boosting others to provide maximum contrast and enhanced visibility. This greater clarity results in reduced reaction times and increased performance over a wide range of light conditions.