The holes in the gauge are used to measure stones, while the extensions are used to measure mountings. One side shows millimeters, and the other side shows the corresponding carat measurements. This gauge includes 19 hole sizes, ranging from 2mm to 11mm in 0.5mm increments:
- 2mm
- 2.5mm
- 3mm
- 3.5mm
- 4mm
- 4.5mm
- 5mm
- 5.5mm
- 6mm
- 6.5mm
- 7mm
- 7.5mm
- 8mm
- 8.5mm
- 9mm
- 9.5mm
- 10mm
- 10.5mm
- 11mm
