Trailer Stabilizing Ratchet Beam Jacks are used to prevent up-ending semi-trailers when they are not connected to a tractor during loading and unloading operations. Also used to level trailers parked on sloped ground and to prevent landing gear from sinking into a soft surface. High strength steel construction. Flush-type zerk fitting for lubricating ACME screw. Powder coat safety yellow finish. Includes reflective collar for visibility at night. Wheel barrel design for ease of positioning, ratchet screw lift and a 6" beam distributes load across front of trailer. Meets OSHA regulations when used with wheel chocks. Lifting Capacity: 40,000 lbs.; Service Range: 39 ½” to 51”; Wheels: 8"D at rear, 4"D at front.