... Precision, Heavy Duty, Uniform Lifting Speed, Low Efficiency, Use Infrequentl screw jack lift Configuration: Worm Gear, Worm Shaft, Taper Roll Bearings, Seals ... locking, Positioning Precision, Heavy Duty, Uniform Lifting Speed, Low Efficiency, Use Infrequently, Easy Installation, Low Noise.* Linear Motions: Elevating,Lowering,Pulling ...