These ballast mounts are CNC machined from solid billet aluminum. Their two piece design is available to clamp to 2" x 2", 2 1/2" x 2 1/2" and 2" x 3" frame rails. They feature a 3/8-16 tapped hole in each side to attach the ballast. These mounts make installing and moving the ballast to the precise location quick and easy.