These bushings go on both sides of the hitch lock provided with 1UP hitch-mounted bike racks. In my case I am using the Super Duty rack with a 2" hitch which measures a little over 2.5" outside (64.4mm).
I printed these out of TPU with 3 walls and 10% gyroid or cross hatch infill. I wanted them to be able to squish a hair to make sure the lock didn't wiggle. You can scale the Z height up or down if needed if your hitch is larger or smaller. Works great for mine (Curt hitch).
The author marked this model as their own original creation.