Hydraulic jack refers to a jack that uses a plunger or hydraulic cylinder as a rigid lifting component. It has the characteristics of compact structure, stable operation, large jacking force, self-locking, and strong jacking capacity.

The method for hydraulic jack to exhaust air: find a rubber plug on the reverse side of the jack, knock it out with a screwdriver, and the gas will also be discharged, and then press the rubber plug back.