Neewer Stainless Steel D Shaft D-ring 1/4" Mounting Screw 0.37"/9.5mm Shaft for Camera Tripod Monopod or Quick Release (QR) Plate Stainless steel D-ring screws for camera tripod quick-release plates. 1/4" metal male thread with 4mm Hex (Allen socket) & hinged "D" Ring Allows the fitment of different styles of plates to fit directly into the base of your camera equipment via the 1/4" screw. Threaded part: 0.22"/5.5mm Head diameter: 0.87"/22mm