SMALLRIG D-Ring Quick Release Camera Fixing Screw 1/4 Inch and 3/8 Inch - 1609 Quick Release Camera Fixing Screw with standard 1/4 The main body was made of Stainless steel, and the Rotatable D-ring made of ZINC Alloys. Please refer to the size to ensure it work with your camera and quick release plate before shopping. Material: Aluminum Alloy Includes: 1x 1/4"-20 screw ,1x 3/8"-16 screw