✔ aluminum alloy, to use. ✔ Filetage métal 1/4 femelle métal 1/4". ✔ This adapter can the shoe to a 1/4 "screw. ✔ 1/4 "screw for L-type camera support bracket. ✔ Total size: approx. 20 x 20mm / 0.79 x 0.79 inch , Inside Diameter : approx. 6.5mm / 0.26inch