... experience in manufacturing MECHANICAL WORM GEAR SCREW JACKS, and complete screw jack. Determination of type1. Type 1 = Screw jack with translating screw Type 2 = Screw jack with travelling nut ... 2. Size = 2.5, 5, 10, 15, 20, 25,35 (×10KN) 3. M = Low worm ... the load from being lowered.All copyright reserved swl series worm screw elevator, screw jack, lift