Geissele 16.5" M-LOK/Arca-Swiss MK18 Black Super Modular Rail 05-791B is a precision-engineered handguard designed for AR-15 pattern rifles, particularly suited for precision shooting and competition use. Featuring a 35mm wide, 45° "Arca Style" dovetail interface, this rail allows seamless mounting to Arca quick-detach bases, providing versatile positioning on tripods and other supports. The rail is precision 3D machined from 7000 series aluminum, offering a balance of strength and lightweight performance. Its M-LOK mounting system at multiple positions ensures flexibility for attaching accessories, while the proprietary 2.25" barrel nut ensures a secure and straight interface with the receiver. Finished in Type 3 hardcoat anodized black, it delivers durability and a sleek appearance. Length: 16.5 inches Attachment System: M-LOK Arca-Swiss Interface: 35mm wide, 45° dovetail Material: 7000 series aluminum Finish: Type 3 hardcoat anodized black Weight: Approximately 17 oz (18.4 oz with barrel nut) Inner Diameter: 1.26 inches Outer Diameter (DAQ): 1.59 inches Barrel Nut: Proprietary 2.25" length for secure interface Compatibility: Mil-spec AR-15 pattern rifles Geissele Automatics Geissele 16.5" M-LOK/Arca-Swiss MK18 Black Super Modular Rail 05-791B