The white color allows the holder to be visibly different. This makes it ideal for UV treatments and other operations that need to be isolated from the lens tints. Holds two lenses. Stainless steel and heat resistant plastic. Only BPIs unique torsion bar design prevents lens warping, scratching, and bending of the lenses while tinting. Select either hand held or gradient models. The solid heavy duty construction prevents pressure from being exerted on the lenses.