Electric Screw Jack can also be called motorized screw jack, it Perfect Steerable Transfer Cartludes a worm gear screw jack and an electric motor.The screw jack can be self-locking acme screw jack or high precision ball screw jack.The motor can be high precision servo motor,stepper motor,helical gear motor, worm gear motor, 3-phase asynchronous motor and 12v,24v,48v do motor and dc gear motor etc.