| Bit size | Bit type | |
| Inch(in) | Metric( mm) | |
| 9 7/8 | 250.8 | SK542G, SK735G, SK835G |
| IADC | Recommendation | Applicable Formation | |
| WOB | RPM | ||
| 542 | 0.4~0.8 | 100~60 | Soft to medium formations with low compressive strength, such as medium soft shale, medium soft limestone, medium soft sandstone, medium formation with harder and abrasive interbed, etc. |
| 735 | 0.6~1.1 | 90~50 | Medium formation and hard formation with abrasive interbed, such as hard shale, hard limestone, sandstone, siltstone, basalt, silexite, granite, quartz sandstone, hard dolomite, hard limestone, pyrite, etc. |
| 835 | 0.65~1.15 | 80~50 | Very hard formations with highly abrasive interbed, such as iron ore, granite etc. |
