A hydraulic jack is a device that is used typically to lift heavy-duty loads, such as cars. The capacity of jacks differ, with some supporting smaller vehicles and others lifting much larger objects such as vans, trucks or more.
The hydraulic jack applies a small force to an area of hydraulic fluid which in turn generates pressure in the fluid via a pump plunger. This build-up of heavy pressure is then applied to a wider area of output, giving it enough force to produce a lift or lowering by the jack.
Jacks are typically small in nature, made from steel and occupy much less space than other alternatives. They are less likely to jam due to rusting on any screw threads.