This fitting is for attaching an AirTag to the rear brake bracket on a RadRunner Plus. It may also work on other RadRunner bikes. The M5 bolts that attach the brake light to the bike frame are about 1 mm longer than they need to be, so there's just enough extra length to clamp this fitting and retain the original washers. This is good because it's unlikely that longer fasteners could be swapped in since they have a non-standard head that fits into the housing of the brake light.

The AirTag goes in the large central hole with the plastic side facing out. Installed, the fitting traps the AirTag against the frame's brake bracket. The fitting has sufficient clearance to use an M8 nut setter to install the fitting.

The fitting is barely visible from the rear (see picture) and inconspicuous when viewed from the front side (from over the rear wheel), though my bike does have the extended seat.

I'd originally planned to spray paint the fitting black, but after the trial installation decided light beige worked pretty well.

Creality

Ender-3 v2

No

Yes

Printed with the large central AirTag hole facing up with supports in the pockets for the fasteners. Removed the supports with a pin punch.