The jack tool (often called the jack handle or lug wrench extension) is the metal rod or crank used to operate the vehicle’s emergency scissor jack. It usually features a hook on one end to engage the jack’s eyelet and a handle on the other to turn it. In many car kits, this tool doubles as the lug wrench (L-shaped) to loosen wheel nuts. Without this specific tool, the portable jack provided with the car is virtually useless. They are often stored in the spare tire well or a pouch in the trunk.