The compact QRA-A2 Quick Release Assembly with QR-10 Plate from Oben is an Arca-type-compatible clamp with a locking knob to lock the quick release plate down. The quick release plate has integrated safety stops to prevent it from sliding out if the clamp is accidentally opened. The dual bubble levels enable you to align the assembly in a horizontal or vertical orientation. At the top of the clamp, the positioning scale helps you to accurately seat the plate and to repeat a previous setup. The 3/8"-16 threaded tripod mount allows you to mount the assembly to a head, tripod, or monopod that does not have a quick release system, and a reducer bushing is supplied for 1/4"-20 threads.