This unit starts with a specially heat treated 1/4″ diameter shaft that has the square receiver integral to the shaft. The shaft is threaded for 1/4-28 nut (included), and has a flat ground for the drive dog setscrew. This ensures that you can remove the drive dog after it has been on the shaft for a while. The specially-made threaded nut that screws into the back of the G-Drive is like a larger version of the ones found on smaller drives, but we make them ourselves in our own factory. We also install long-wearing “Oilite” bronze bearings to support the shaft as it rotates. Every single piece of the propshaft unit is replaceable, because we all know, things just wear out. Includes propshaft, threaded nut, thrust washers, drive dog and 1/4-28 nut.