This Meprolight USA MPO PRO-F Optic Adapter Plate features a durable matte black aluminum construction designed specifically for large frame Glock MOS models (such as Glock 20, 21, 29, 30, 40, and 41). Engineered to provide a secure, low-profile mounting interface between your firearm slide and red dot optic, it includes all necessary mounting hardware for installation. Safety Note Always ensure the firearm is unloaded before installing or adjusting any optics or adapter plates. Verify proper torque specifications during installation. Improper mounting may affect accuracy and safety.