This Baseline Arca Dovetail from MID49 with Arca-Swiss standard camera dovetail. It features a center screw slot that accommodates the included 1/4"-20 and 3/8"-16 captive camera tie-down screws. This slot enables you to adjust the camera forward and back to help balance your camera. The integrated lens support clamp allows you to add a lens support post when working with heavy lenses or lens adapters.