SWL Screw Lift 1.in line with JB/T8809-1998 (original JB/ZQ4391-86) standard 2.Carrying capacity ... of the 2.5-120T SWL Screw Lift Description:Screw lift, SWL series ... support, high reliability, long life. 1, structure type Lift divided by structure type: Type 1 - same as ... and slow (M). 5, the protective screw screw lift the protective type 1 is divided into: basic, ...