The PU-40 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. Safe screw installed in both side to prevent drop of camera by accident. You can change the location of the screw to fit different cameras. The PU-40 universal quick release system has been designed to be compatible with other brand quick release systems. Suitable for most ball heads. Specification: Material: Metal Alloy Color: Matt Black Length: 40mm/1.57 inch Width: 38mm/1.49' (Universal width of Arca-Swiss Standard QR Plates). Thickness: 10mm/0.39' (Universal Thickness of Arca-Swiss Standard QR Plates) Mounting Screw Diameter: 1/4" (The Screw Size That Connecting the QR Plate and Camera) Compatibility: Arca-Swiss Standard Package Includes: 1 Piece 40mm Quick Release Plate 1 Piece 1/4 inch Screw : Please allow 1-3mm differs due to manual measurement. Due to the different display and different light, the picture may not show the actual color of the item. Thanks for your understanding.