I have kids safety flag in my wheel loader, due passenger car drivers have problems figuring out how wide wheel loader is in traffic....
Pole OD is ~6mm, hole ID in topper is ~6.2mm, i attached with glue.
Similar for this: https://www.walmart.com/ip/Sunlite-Bicycle-Safety-Flag-72in-Orange-2-Piece-Bike-Axle-Mount-High-Visibility/31974018
Flagpole_topper_for_bike_safety_flag.stl | 75.3KB |