Bal Stabilizing Jacks are designed for fine leveling and stabilizing travel trailers and 5th wheel trailers. The Telescopic Type is the most popular because it requires no existing trailer frame crossmember for installation. The unit will telescope to fit any underbody frame width. Fits most trailers front or rear. Telescopic jacks are mounted as an assembled unit. Set of 2 jacks with crank handle, per box.