About two months ago I replaced our three step unit with a quad step and am happy I spent the money. I think the brand was Stromberg, but not sure and the trailer is at the storage lot. Changing them was simple, loosened the 4 bolts, put my floor jack under it with a board wider than the steps , then removed the bolts and lowered it, took the old one off, put the quad on the jack and board, then raised it, lined the bolts and finished the job. Maybe took 30 minutes. Now need to sell the old 3 step unit so it's off the garage floor.