Easy to operate using the chromed crank with speed handle. Rust-resistant, heavy-duty steel jacks extend from 4" (closed position) to 24". Tooth gears ensure straight-line vertical extension/retraction of scissor arms. Large (8" x 5") base plates provide steady support. 3" x 7" mounting plates can be attached to vehicle using large sheet metal screws (included) or can be bolted or welded to frame. Set includes 2 jacks and one crank. Order 2 sets to level/stabilize both front and rear of vehicle. Limited lifetime warranty.