Standard: API Spec7 and SY/T6509, AISI 4145H
Main Parameters:
| Size | Lengthin | Upper box connection | Lower pin connection | I.D. | Driving section |
| mm | in | Type(LH) | O.D. | Thread | O.D. | Cross flat | For square kelly | Cross corner for hexa kelly |
| Std | optional | Std | optional |
| 63.5 | 2 1/2 | 12.19 | 6 5/8REG | 4 1/2REG | 196.8 | 146.0 | NC26 | 85.7 | 31.8 | 63.5 | 83.3 | |
| 76.2 | 3 | 12.19 | 6 5/8REG | 4 1/2REG | 196.8 | 146.0 | NC31 | 104.8 | 44.4 | 76.2 | 100.0 | 85.7 |
| 88.9 | 3 1/2 | 12.19 | 6 5/8REG | 4 1/2REG | 196.8 | 146.0 | NC38 | 120.6 | 57.2 | 88.9 | 115.1 | 100.8 |
| 108.0 | 4 1/4 | 12.9 | 6 5/8REG | 4 1/2REG | 196.8 | 146.0 | NC46 | 158.8 | 71.4 | 108.0 | 141.3 | 122.2 |
| 6 5/8REG | 4 1/2REG | 196.8 | 146.0 | NC50 | 161.9 | 71.4 | 108.0 | 141.3 | 122.2 |
| 133.4 | 5 1/4 | 12.9 | 6 5/8REG | | 196.8 | | 5 1/2FH | 177.8 | 82.6 | 133.3 | 175.4 | 151.6 |
| 6 5/8REG | | 196.8 | | NC56 | 177.8 | 82.6 | 133.3 | 175.4 | 151.6 |
API Kelly (For oil drilling)
