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
