The SRB-38 Quick Release Clamp from FLM is a 1.5" / 3.8 cm open channel clamp that accepts most Arca-type quick release plates. The clamp features a knurled locking knob, a 3/8"-16 bottom mounting thread, and a plate restraining pin and iIncludes an integrated spirit level. Arca-compatible and adjustable to various Arca plates.