Lifting tools include jacks and stands, which are used to lift automobiles off the ground or lift vehicle components to allow for maintenance. Air, mechanical, and hydraulic floor jacks are used to lift vehicles and other heavy weights using air or hydraulic power. Bottle jacks are small hydraulic jacks that may be stowed in a vehicle and used for on-the-go maintenance like changing tires. Engine supports lift and support engines so mechanics may inspect and repair them from all angles. Motorcycle and ATV lifts, as well as plow jacks, are designed to elevate motorcycles, ATVs, and other compact engines. The head of transmission jacks can be adjusted to align with transmission bolt patterns and pins. To jack up and support either side of a vehicle, stands are usually employed in pairs.