... Duty, Uniform Lifting Speed, Low Efficiency, Use Infrequentl worm screw liftConfiguration: Worm Gear, Worm Shaft, Taper Roll Bearings, ... ,Rolling.* Manual Operation and Electrical Operation are available.* Multiple Screw Jack Systems are availbale and fully synchronized.* Absolutely irreversible ... other locking systems.* Three reduction ratio are available for each model. Fast ratio,1 turn shaft,1 ...