30" Camera Rain Cover.Fits SLR's with a 500mm or 600mm f/4.0 lens. This cover will fit: Cameras with a 500mm f/4.0 or 600mm f/4.0 lens & hood. Other camera+lens+hood combos that are up to 27" long. Other key features: Dials & buttons are visible when cover is held against the camera. Fits with an external flash on the camera. TTL flash works with the cover on. Works with lenses that rotate to focus. Compact & ultralight. 30" cover weighs ~2 oz. Made with silnylon -- a waterproof and very durable fabric. The cover has an elastic cord & lock on both ends. You attach the cover around the lens, and leave the back end open however much you want when you're shooting, and close it down when you're not shooting. NOTE--the cover looks opaque if it's not touching the camera, but is remarkably transparent when it's touching something -- see photos.