The red HD lens is best used on sunny to slightly cloudy days.Features:- Spherical Fusion Double Lens (FDL)- HD Lens Technology- Stereo Lens Technology- Supreme Anti-scratch Outer Lens (PC)- Hydrophobic Lens Coating- 8x Anti-fog Inner Lens (AC)Technology:Lense Construction:- FDL is the next-generation for double-lens construction: it uses lamination instead of connecting the lenses with an additional foam layer, which means a larger field of vision, and no refractions, reflections or fogging. All our Fusion Double Lenses are of optical class 1.Cylindrical Fusion Double Lens:- With the cylindrical double-lens the field of vision gets larger by 15%Spherical Fusion Double Lens:- Spherical double-lenses have a 20% larger field of visionHd Lens Technology:- HD (High Definition) technology gives crystal clear visibility in all light conditions. Crystals in the lens divide white light into its six spectral colors. The lens then enhances the sensitive ones, so you see everything in high-definition contrast and get a greater sense of depth, making these the best performing lenses in the widest range of light conditions.Stereo Lens Technology:- Nine layers of high-end mirror coating increase protection from glare and reduce eye fatigue - with the colors and coatings perfectly balanced for 100% clarity.Photochromic Lens Technology:- Our photochromic lenses respond to changing light conditions by adjusting the level of tint. When it’s dark they get lighter. When the sun comes out they get darker to protect you from glare.Flash Lens Technology:- Flash lens technology includes one layer of high-quality mirror coating.Classic Double Lens:- Our classic double-lens goggles use the classic construction - this features an anti-fog inner lens (AC) and an anti-scratch outer lens (PC) connected with a foam layer.Optical Class 1:- All our lenses feature class 1 optics - minimizing distortion and eye fatigue. They’re 100% UVA/B protective and comply with highimpact resistance standards8 X Anti-fog Inner Lens (ac):- The inner lens of all our FDL lenses offers up to 8x more anti-fog properties than industry standards, withstanding fogging for over 240 seconds in controlled lab tests (vs. the standard test length of 30 seconds).Hydrophobic Lens Coating:- A durable coating that repels moisture, grease and dirt. Water drops roll off and disperse without streaking, while fingerprints can be easily removed.Supreme Anti-scratch Outer Lens (pc):- Our quality double lenses have a hard coating on the outer lens with excellent anti-scratch properties so you’ll always have a clear view.