LensCoat for the Sigma 50-500 OS. LensCoat Sigma 50-500 OS telephoto lens cover offers your valuable equipment some protection from scrapes and bumps, preserving its resale value. It also helps break up the shape of your lens, making it less noticeable to wildlife. The LensCoat Sigma 50-500 OS features a clear plastic windows over the auto focus controls, zoom lock and also the distance scale. *This cover comes with an optional piece for the lens is zoomed out to 400mm which can be quickly and easily put on and removed with its Velcro attachment as seen in the picture.