The MK18 is the latest in the line of Geissele Super Modular rails and is specifically made to interface with the Arca-Swiss Quick Release System. This new handguard is based on the MK16 M-LOK Super Modular Rail, offering a small diameter and overall height creating a slim profile for competition shooters. The flat base of the MK18 features an "Arca-Style" 35mm wide form with a 45 degree dovetail, that allows quick mounting to an Arca-Swiss Quick Release mounting base, sliding into any position along the rail. The MK18 features Geissele's proprietary 2.25" long barrel nut that interfaces with the receiver and creates a platform that can be trusted to be straight an Mfg: Geissele Automatics