This is a shoulder screw that is used to secure the handles of yard equipment. Typically, this screw is used with a matching wing nut, which is sold separately. Many different varieties of push lawn mowers have handles that fold downward for ease of storage. This is one of the locations on a mower where one will find shoulder bolts and the point at which these bolts are most likely wear out. While they are made of durable machined metal, shoulder bolts receive a great deal of wear, particularly from the handles being raised and lowered each time the mower is used. When pushing down on the mower to clear wet grass clippings or to make sharp turns with the mower, the entire weight of the mower is put on the two shoulder screws where they intersect. Since the metal of the handles can turn at that juncture, extra shearing action is put on the shoulder bolts, which can wear out. It is actually advantageous that the bolts wear out since otherwise, the handles themselves would warp and break apart. These OEM genuine replacement parts fit a number of different lawn and garden machines, including many made by Cub Cadets, Husky, Troy-Bilt, Craftsman, Yard-Man, Bolens, MTD, and Yard-Machines.