Cheap 100% S2 Sunglasses Black Frame HiPER Deep Blue Lens keep your face cool and dry while keeping the lens free of fog. The downside to the excellent ventilation is that the circulating air behind the lens can bring dust and debris. At higher speeds, you can feel air movement behind the lens, and we found that these glasses don't do a great job of protecting your eyes from dust when following close behind another mountain biker.