The B1DMkIII Plate for Canon 1D Mark III and Mark IV from Really Right Stuff is designed specifically for these cameras and with anti-twist flanges that keep the mounted camera from twisting. Once the dovetail plate is on, quick release functionality has been added to the camera. Also, this base plate is compatible with all Really Right Stuff clamps and most other Arca-type heads.
The CNC machined 6061-T6 aluminum plate maintains complete access to the battery door without obstructing the LCD monitor of the camera. The plate itself is resistant to scuffs and scratches because of the type II black anodizing. Furthermore, the base plate has a laser-engraved center mark on the back to align it on a tripod head.