Spin Right Aluminium Spinners - All Spinners come with matching backplate and prop nut -The spinner cones are lathed, machined and finely polished from high quality aluminium alloy, with nickel-plated prop nut, bronze brushing and back plate made from cold-rolled aluminium plate. - The perfectly concentric fit relative to the engine axle and propller, provides maximum strength at extreme RPM Avaliable in Different Sizes 1.5" 3" 3.5" 3.75"