These rear axle chain adjusters are based on the stock Harley-Davidson adjusters, OEM #9020-2, found on K Model bikes and Ironhead Sportsters 1952-1980. The difference is these are made for use with a 3/4 inch rear axle with 5/16 24 TPI threads . These are for use on custom built motorcycles, or for Ironhead Sportsters running different rear wheels. Cadmium plated. Includes two axle adjusters and four nuts.