This B2-AS-II Lever-Release Clamp with 1/4"-20 Screw from Really Right Stuff is compatible with most Arca-type camera plates, lens plates, and multi-purpose rails. The jaws of the clamp open wide for plates to be top-loaded quickly and easily with no mishandling of the camera during mounting.
The locking lever-release is opened or closed by only using finger force, and once the clamp is locked down onto the plate, it has a holding power of up to 50 lb. At the top of the clamp, it features a non-threaded, counter-sunk center socket, which mounts through the top via a 1/4"-20 mounting screw. The clamp is compatible with Really Right Stuff, some Arca-Swiss, and Manfrotto ball heads.
The CNC machined 6061-T6 aluminum clamp has a type II black anodized finish. Index marks are laser-engraved on both sides of the clamp so a position can be repeated. Additionally, the stainless steel locking-lever has a low profile, and the lever hugs the side of the clamp very closely, so it is very unlikely to snag onto clothing or something else in the field.