American Defense Mfg. AD-509T, Optic Mount, Lower 1/3 Height, Anodized Finish, Black, Quick Release, Fits Holosun 509T Footprint AD-509T-11-STD The American Defense Manufacturing AD-509T Optic Mount Lower 1/3 is a high-quality mounting solution designed specifically for the Holosun 509T footprint. It provides a lower 1/3 co-witness height for use with iron sights, allowing for a more comfortable shooting position and improved sight picture. The mount is constructed from durable aluminum and features an anodized black finish, which provides corrosion and wear resistance. It also has a quick-release mechanism that allows for easy installation and removal of the optic without the need for tools. Overall, the American Defense Manufacturing AD-509T Optic Mount Lower 1/3 is a reliable and sturdy mounting option for the Holosun 509T footprint, providing a secure attachment to your firearm and ensuring that your optic remains in place, even under heavy recoil.