The OpticGard Scope cover for the Holosun® 509T offers protection against stray casings and scratches. The intelligent cut allows the cover to fit most rear and suppressor sights. It also includes a detachable training lens which will allow you to use the red dot even in the sun or bright areas. Our scope covers are made from a material made from TPU (Thermoplastic Polyurethane) offering protection from abrasion. In addition, the fast and simple installation allows easy access to the buttons without removing the cover. Finally, the interlocking pins secures the cover so it won't fall off even with heavy recoil from handgun slides. Are you tired of taping your optic for occlusion training? Our removable training lens is the modern solution! Note: Important Information Not compatible with Holosun® 509 ACSS Vulcan OpticGard Covers may not be compatible with backup sights that are mounted in front of the optic. Sufficient space is needed for the cover to latch onto the front of the optic housing. OpticGard will add approximately 0.08 inches (2mm) to the sides of the optic. If using in conjunction with a holster, please make sure there is sufficient spacing between the holster with the cover on.