Size guide
| SIZE | INSIDE DIAMETER |
| 2 | 14 mm |
| 4 | 14.2 mm |
| 6 | 14.6 mmm |
| 8 | 15.2 mm |
| 10 | 15.9 mm |
| 12 | 16.5 mm |
| 14 | 17.1 mm |
| 16 | 17.8 mm |
| 18 | 18.4 mm |
| 20 | 19.1 mm |
| 22 | 19.9 mm |
| 24 | 20.4 mm |
| SIZE | INSIDE DIAMETER |
| 2 | 14 mm |
| 4 | 14.2 mm |
| 6 | 14.6 mmm |
| 8 | 15.2 mm |
| 10 | 15.9 mm |
| 12 | 16.5 mm |
| 14 | 17.1 mm |
| 16 | 17.8 mm |
| 18 | 18.4 mm |
| 20 | 19.1 mm |
| 22 | 19.9 mm |
| 24 | 20.4 mm |