These black powder coated, bolt-on solo seat spring mounts fit Harley-Davidson Big Twin frames from 1958 through 1985. This includes Panhead, generator Shovelhead and cone Shovelhead powered motorcycles. These seat spring mounts conveniently fit over the threaded end of the shock studs (the heavy-duty studs that hold the top of the shocks to the frame) and are held in place with the stock nuts. This gives a secure and tidy way to support the solo seat springs when mounting a sprung solo seat. Made in the USA.