The 3500 / 5000 QuickJack hydraulic cylinder completely eliminates the need for clumsy screw mechanisms, and it fits both the BL-3500SLX and BL-5000SLX car lift models. Constructed from the same rugged 14-gauge welded steel as the rest of the frame, the hydraulic cylinder is securely machine-welded to the air cylinder. Both features assist with the raising and lowering of the frame. Comes in two sizes for the 3500/5000 or 6000/7000 model.