Pu-50 Quick Release Plate For Benro Sirui Tripod Ballhead Fit Arca Swiss The PU-50 Slide-In Quick Release Plate has a 1/4"-20 thread and is a spare or replacement part for Ballheads and other Arca-Swiss compatible Quick Release clamps Width: 38mm (universal width of Arca-Swiss Standard QR plates). Thickness: 10mm (universal thickness of Arca-Swiss Standard QR plates)