Designed with the help of some of the world's top base jumpers, the Julbo Tensing Flight Sunglasses are designed to handle the most extreme activities. The Zebra photochromic lenses react to changing light conditions in a short twenty two seconds so you can adapt quickly when you only have a small window of time. An anti fog coating prevents fogging so you don't have to worry about getting blindsided at a critical time, and the hydrophobic coating repels moisture in case a sudden rain or flurry rolls in. The Tensing Flight also comes with a spare polarized lens that reduces glare, which comes in handy when you're surrounded by water or snow. The lenses are also extremely lightweight, yet durable, so they won't shatter in case of an accidental impact. When you're getting ready to experience some Gs, swap out the temples for one of the two elastic headbands included. The band, along with the bi density frame, creates a snug fit that keeps drafts out so your eyes don't water up when you're hitting high speeds.