Allows you to add an extra bearing at the end of the shaft of the stepper motor in a Bulldog Lite setup. This should provide some relief when tightening the tension screws really hard. The bearing is 10x4mm. Edit: did not help with the motor skipping steps. The E3Dv6 demands a bit too much from a non geared Nema 17 in this configuration. Upgrading to a geared one solved that problem. A shaft relief is probably not a bad idea anyway.This one came about since I suspect the reason my printer skips steps once in a while. Modelled in Inventor Fusion for Mac.