This is the 2 ball bearing installed compatible level winder worm shaft of ABU 1500C, made by aluminum alloy to remove weight. This new version has a screw fastening the gear to the shaft, and you may change ball bearing at the shaft. Fits to 1500C, 1600C, 1601C with metal cup washer at level winders. Doesn't fit to the oldest models without the metal cup washer. 4.1g (genuine worm shaft 5.6g) Ball bearings removes friction in rotation drastically. Plastic part is made of Duracon POM to offer friction-less operation.