The Rudy Project Rydon is unbelievably lightweight in 22grams, it's flexible yet durable and our best selling product for Sports Prescription. The Rydon has been a best seller for Rudy Project for 16 years and still will be selling for another 100 years. Therefore support down the track for spare parts, lenses and RX will not be a problem. Features include: adjustable nose piece and temple, E-Lock patented anti-slip nosepiece locking system, prescription ready. The Rydon Photochromic BLACK lens tint is our best selling lens and changes colour from complete clear to a nice black grey tint and is activated by light as well as UV light. The Rydon Photochromic Black lenses are very sensitive and work better in humitity and altitude compared to regular transition lenses. This Photochromic Black lens is classified as a daily lens and great for all conditions especially road cycling, triathlons, road running, marathons, daily use.