This stump jumper is constructed from heavy duty steel to help prevent rocks and debris from breaking, clipping or getting caught in the blades. This diameter measures 20-1/4 inches, and there are two bolt holes that measures 13-1/2 inches apart. The center hub has 12 splines, and measures 1-1/2 inches in diameter. This rotary mower stump jumper is compatible with most rotary mowers that use a 40 horsepower gearbox
