The swing-back bolt-on trailer jack is painted with Zinc, which is corrosion resistant. The height is adjustable from 10-1/2 in. to 20-1/2 in. Fits trailer tongues 3 in. to 5 in. and helps easily raise and lower any trailer up-to a 1/2-ton (1,000 lbs.) capacity. Equipped with a sturdy 6 in. wheel that provides low-friction mobility, allowing you to move your trailer into position easily.