NOSEN RNV-065 small bevel gearbox with RNF016 small screw jacks, hand operated adjust conveyor systems. Common to most small screw jacks for conveyor systems are ... the following elements:1. Inverted type jacks,self-locking screw, clevis end and ... very short, usually, 60 mm~80 mm.6. Manually operated. Small Screw Jack Adjusts Conveyor Systems