Bicycle U-Lock Holster for Track Bike Rack

Kryptonite® makes a wobbly holster for their locks that isn't optimal for their longer U-locks. I use a Topeak® Trunk bag that slides into a compatible track on their rear bike rack. When I'm not using the bag, I don't have a great place to stow my lock. 

This U-lock “back seat" slides into the rack's track (QuickTrack®). They even make a track adapter for other racks.

Video (Twitter)

Print it with the optional 3x6 mm magnets! The *.gcode file here will pause 3 times so you can insert them. These magnets allow you to stow the back piece up against the front one while not in use, such as when the bike is locked up. 

Support is required to achieve good geometry on the track part of the print. The *.3mf file contains two parts. Print them on their side as shown in the *.gcode render.