The B550D-L L-Plate for Canon 550D from Really Right Stuff is machined from a solid block of aluminum and a fixed L-plate is created, which can be changed while on top of a tripod, from a vertical to a horizontal position, without sacrificing your center of axis.
The Arca-type compatible dovetail plate adds quick release functionality to the camera, and an anti-twist flange and the 1/4"-20 mounting socket keep the camera body from moving. Also, the L-plate maintains complete access to the battery door and the camera's ports. Type II black anodizing has been applied to the CNC machined 6061-T6 aluminum. The anodizing has given the L-plate a smooth surface, which is resistant to scuffs, scratches, and corrosion. Also, the L-Plate has laser engraved center marks on the back of each axis for alignment on a tripod head.