... Shaft, Taper Roll Bearings, Seals, Housing, Self-locking Trapezoidal Screw,etc;3. Safely self locking, Positioning Precision, Heavy Duty ... Manual Operation and Electrical Operation are available;6.Multiple Screw Jack Systems are availbale and fully synchronized;7.Absolutely ... ,Electric Motor,Motor Flange,Frequency Inverter,Safety Nut,Steel Cover,Rubber Belllows,Limit Switches,Couplings,Flexible Linking ...