This item is an Era-Tac KeyMod Accessory, for use with KeyMod Systems. Specifically, it is a 5-slot Picatinny rail. Era-Tac continues their forward-thinking development of useful accessories for the competition and tactical marksman with the release of several Mil-Spec, high-grade aluminum KeyMod Accessories (compatible with KeyMod systems).Fully-machined from solid, high-grade aluminumAll parts are Mil-spec, Type-III anodized (black), rendering them corrosion-proofNo losable componentsSecure with Torx Screws and Nuts (also available) ERATAC Key Mod Picatinny Rail 5-slot T4905-0010