Material: Aluminum. Mounting screw diameter: 3/8" and 1/4". Quick release plate 501PL for 701HDV 501HDV 503HDV MH055M0-Q5, compatible with heads using the RC5 quick release system. Includes one 1/4"-20 camera screw and one 3/8", as well as a guide (video) plate. Soft padding for camera protection. Precisely designed, black anodized, corrosion and abrasion resistant.