Bộ Test Ép Khít Nam Châm (Magnet Press Fit Tester)

Six pockets, left to right: crush ribs, then plain bores at 6.0, 6.1, 6.2, 6.3, and 6.4 mm diameter.

Each pocket has a centre push-out hole (3 mm) so you can recover magnets after testing.

(the one I printed had some labels that came out poorly, so I decided to remove them but wasn't worth reprinting)