MDT M-LOK Arca Rail, 7, Anodized Finish, Black, Aluminum Construction, Fits M-lok 103568-BLK Securely attach your rifle to an ARCA mount with the MDT M-LOK ARCA Rail. Arca Swiss adapters have become the standard for attaching rifles to tripods" bipods and support gear. Need to attach your MDT Chassis rifle to an ARCA interface? Use MDT's M-LOK ARCA Rail. The MDT M-LOK ARCA Rail is Mil-spec Type II hard-black anodized. Available as a standard" flat profile that can adapt to most M-LOK compatible surfaces.