worm-bolt lifter Made of high-quality aluminium alloy light weight and non-rusting. Large output torque. Smooth running SLSWL series worm-bolt lifter, combined of worm unit and echeion boft for lifting up or moving down,compact in structure,light and portable,flexible,refiable,long in service life,easy to intallation and self-iocking while stopping.Technical DataModelSWL1.0SWL2. ...