With the Onyx ARL mask, we have taken one of our best selling masks in theOnyx and upgraded the lenses with an Anti Reflective coating. These AntiReflective Lenses (ARL) start as Sherwood Crystal Clear lenses and are treatedwith the Anti Reflective coating. This process of coating the lenses reducesthe amount of light that is reflected by the Crystal Clear lenses. Thispermits additional light to pass through the lenses to the divers eyes. Theadditional light translates into improved contrast and optical clarity.Typical tempered lenses allow 92% of the light to pass through. Crystal Clearlenses allow 95% of the light to pass through. ARL lenses allow 98% of thelight to pass through to the divers eyes.