For the easy measurement of the outer diameter of pipes and other round objects. These calipers are made of hardened steel with tips of tempered steel.
| Code | Size mm | Code | Size mm |
| 650101 | 100 | 650107 | 350 |
| 650102 | 125 | 650108 | 400 |
| 650103 | 150 | 650109 | 450 |
| 650104 | 200 | 650110 | 600 |
| 650105 | 250 | 650111 | 750 |
| 650106 | 300 | 650112 | 1000 |