Haoge 58mm Screw Knob Clamp Adapter with 60mm QR Quick Release Plate for Camera Tripod Ballhead Monopod Ball Head Fit Arca Swiss Haoge CP-58 Quick Release Clamp + QR-60II Quick Release Plate for Tripod Monopod Panoramic Ball Head Compatible Arca-Swiss The Haoge 58mm (2.28") Discal Clamp is a Arca Swiss compatible screw knob clamp. It will accept any standard Arca-Swiss quick release plate. There is a 3/8" threaded hole at the center for mount the clamp onto a tripod or monopod, and also comes with a 3/8" to 1/4" screw adapter. The 60mm slide-in quick release plate has a 1/4"-20 connecting screw and two safety stop screws.