This nifty item is not only a tripod reducer that will convert a 3/8" tripod stud to 1/4", it is also an Arca compatible platethat can be mounted in 2 axis's.Solid, 1 piece aluminum construction, with rubber mat. Overall diameter: 50mm Diameter of rubber mat: 42mm.Weighs 40g (1.4oz)Includes 2 2.5mm safety screws & allen wrench. Please note: the 1/4" screw is fixed and does not rotate. ***Please note: This plate is not compatible with RRS Lever Clamps. (RRS Levers are not adjustable).***