20 Ton Heavy Load Screw Jack Manual Operation 500 MM Stroke For Power Station Damper. Model JT-20T-IS-1000-L-II-C-PP/BB. Spindle lifting screw sizes Tr64x10, 20ton maximum tension lifting force, inverted mounting, translating screw configuration, travel length 1000mm, low gear ratio 40:1, clevis end, double input worm shafts, protective pipe and bellows boots.