This 5.7" MPR-CL Rail with Integral Clamp from Really Right Stuff is made to mount to the bottom of a camera plate or L-bracket. The double-dovetail design accepts accessories, which mount to the top or the bottom of the rail, which is also Arca-type compatible.
When the MPR-CL rail is mounted on a ball head, it can be used as a macro slider or focuser for a camera. A laser engraved scale, in 1mm increments, can be found on both sides of the rail. Additionally, Really Right Stuff and Wimberley flash brackets are compatible. Acting as a nodal slider on panoramic gear, the rail allows for better panoramic images by keeping the camera centered over the axis of rotation. The CNC machined 6061-T6 aluminum rail has a Type II black anodized finish.