The internal hook is used for fishing all kinds of ropes and other failing objects from the casing or tubing, such as steel wire rope, logging steel wire, paraffin cutters, etc. The internal hook can be inserted into the ropes or other failing objects. When lifting the drill stem, the hook teeth will catch the objects and take them to the ground.
| Model | OD | Connection | Casing Tubing Size |
| mm(mch | |||
| NG73 | 73(2-7/8) | 2-3/8UP TBG | 3-1/2”Tubing |
| NG95 | 95(3-3/4) | NC26 | 4-1/2”Tubing |
| NG114 | 114(4-1/2 | NC31 | 5-1/2″Casimg |
| NG150 | 150(5-29/32) | NC38 | 7″Casimg |
| NG190 | 190(7-31/64) | NC50 | 9-5/8″Casmg |