Hejnar Photo Arca Type Conversion Set for Manfrotto 405 Gear Head - Made in U.S.A Plate and Clamp Weight 11 oz (340g) Plate Specyfication: 3.56 inches long, 2.56 inches wide, 5/8 inches thick ( without clamp) Precision C.N.C. machined from 6061-T6 Aluminium. Stainless steel hardware. Black hard coat anodized surface.