| Inches | 3" | 3.5" | 4" | 4.25" | 4.5" | 4.75" | 5" | 5.25" | 5.5" | 5.75" | 6" |
| Centimetres | 7.5cm | 9cm | 10cm | 10.5cm | 11.5cm | 12.cm | 12.5cm | 13cm | 14cm | 14.5cm | 15cm |
The Shires bit mouthpieces are measured are measured from the inner ring hole edges.
| Inches | 3" | 3.5" | 4" | 4.25" | 4.5" | 4.75" | 5" | 5.25" | 5.5" | 5.75" | 6" |
| Centimetres | 7.5cm | 9cm | 10cm | 10.5cm | 11.5cm | 12.cm | 12.5cm | 13cm | 14cm | 14.5cm | 15cm |
The Shires bit mouthpieces are measured are measured from the inner ring hole edges.
