A bottle jack is so named because it is shaped like a bottle. The upright, cylindrical shape allows you to place it in tight spaces where other jacks may not fit. It is hydraulically driven and the operator uses a handle to pump up the jack. As the jack rises, it raises the equipment under which it is placed.
An inflatable jack uses air or water to lift. The jack is lightweight and easily portable. It fits into small spaces where there is not enough clearance to insert other types of jacks. The inflatable jack resembles a deflated pillow. You place it under the equipment that you need to raise, then air or gas is pumped into the jack, forcing it to expand and lift the equipment.
A ratchet jack uses a gear and a pivoting mechanism called a pawl that falls into notches on the gear to lock and hold the gear. This mechanism incrementally raises an object and holds it until released. These come in various styles and strengths. They are operated typically by pumping a lever up and down but may have a handle that is turned on models designed to lift small amounts of weight.
A scissor jack is shaped like a square balanced on one of its points when at its midway lifting point. From there it either flattens out as it is lowered or brings its sides together as it raises. It is moved up or down by turning a bolt that runs through the center from side to side.