1. Pure copper oil steel tip, high hardness, good toughness, not easy to rust
2. Hexagonal interface, fine thread, precise and durable
3. Small pitch, good self-locking, seamless connection, not easy to leak oil
4. Precision instrument lubrication, good penetration
5. Material: copper
6. Size: about 3.4x1.2cm/piece
7. Weight: about 10g/piece