... feature: high efficiency,high accuracy,use frequency,self-locking,long life ball screw jack description:1.Model: RNK-0.5T,1T ... 20T2.Configuration: worm and worm gear,bearing,housing and ball screw3.Ball screw jack assemblies use small balls to roll between ... than Lead screw jack7.Ball scrwe jack feature:high efficiency,high accuracy,use frequency,self-locking,long lifeAccessories: Protective Tube, ...