B-66 Impregnated Diamond Core Bit
| Size | B-66 | Design | Metric |
| Outer diameter MAX (mm) | 66.12 | Outer diameter MAX (in) | 2.603 |
| Outer diameter MIN (mm) | 65.87 | Outer diameter MIN (in) | 2.593 |
| Inner diameter MAX (mm) | 51.81 | Inner diameter MAX (in) | 2.040 |
| Inner diameter MIN (mm) | 51.56 | Inner diameter MIN (in) | 2.030 |
| Hole diameter (mm) | 66.5 | Hole diameter (in) | 2.61 |
| Core diameter (mm) | 51.7 | Core diameter (in) | 2.04 |
| Hole area (cm2) | 34.5 | Hole area (in2) | 5.35 |
| Core area (cm2) | 21.0 | Core area (in2) | 3.26 |
