- Check the flatness and parallelism of measuring faces of micrometer
| Code | Parallel Included | Applicable Micrometer |
| 4184-41A | 15.62mm, 15.75mm, 15.87mm, 16.00mm | 0-25mm |
| 4184-42A | 40.62mm, 40.75mm, 40.87mm, 41.00mm | 25-50mm |
| 4184-43B | 65.62mm, 65.75mm, 65.87mm, 66.00mm | 50-75mm |
| 4184-44B | 90.62mm, 90.75mm, 90.87mm, 91.00mm | 75-100mm |