This small troubleshooting print conserves filament. It contains a 0.8 mm mating-surface coupon with three openings—25.0, 25.4, and 25.8 mm from left to right—and a Ø24.606 × 25.4 mm test pin.
The 25.4 mm opening represents the crown socket. The adjacent sizes help identify whether the current printer and material are producing tight or loose.
Bambu validation has been close to modeled size, so this check is optional—not a required first-run calibration.