Sold as a pair of pivot cups
100a Machined urethane pivot cups.
These were not designed for a specific truck brand, so here are the measurements.
Outside Diameter 19.25mm
Inside Diameter 12mm
Total Height 16.6mm
Top of Pivot to Bevel is 14.1mm
These look like they are real close to a Vintage Bear Grizzly Gen 4 or earlier or similar pivot cup.