Mechanical jack refers to screw jack. There are many kinds of jacks, including mechanical jacks and hydraulic jacks. Their structures are very different. There is liquid inside the hydraulic jack and the hydraulic jack. And the mechanical jack, as its name implies, is all mechanical, so it can be jacked in any direction. And relatively strong and durable. There are many specifications of screw jacks, ranging from 3.2 tons to 100 tons. There are many load specifications. It can be used for bridge construction and factory building jacking.