- For quick measurement of inside diameter of deep holes and width of slots
- Satin chrome finish
| Code | Range | L | Øa | Øb | Øc |
| 4209-1 | 8-12.7mm | 250 | 3.9 | 2.9 | 6.2 |
| 4209-2 | 12.7-19mm | 250 | 5.3 | 3.8 | 6.2 |
| 4209-3 | 19-32mm | 250 | 5.3 | 3.8 | 6.2 |
| 4209-4 | 32-54mm | 300 | 7.6 | 6.1 | 7.2 |
| 4209-5 | 54-90mm | 300 | 7.6 | 6.1 | 7.2 |
| 4209-6 | 90-150mm | 300 | 7.6 | 6.1 | 7.2 |