... structure 2. Generator control panel 3. fast and easy assembly 4.stable operation 5. rich experience SJ series ... worm ball screw or screw jack•SJ screw jacks are trapezoidal screw ... : SJ5, SJ10, SJ25, SJ50, SJ80, SJ200. 2. The dimension of screw isTR18*4, TR22*5, TR30 ... irrigation, chemical industry, healthecare and so on. SJ series worm ball screw or screw jack