Kelly is a square or hexagonally shaped steel pipe connecting the swivel to the drill pipe that moves through the rotary table and transmits torque to the drill stem. Customer Options: 1. Standard: API 7-1; SY/T 6509; or Non-Standards. 2. Type: Square Kelly; Hexagonal Kelly. 3. Steel Grade: AISI 4145 H. 4. Size: OD (3 1/2\'\'---6\'\') * ID (1 3/4\'\'---3 1/2\'\') * Length (40\'). 5. Cold Rolling of Thread Roots 6. Stress Relief Groove 7. Thread Surface Process: Phoscoating or Copperize Process Treatment. 8. Cast Steel Thread Protector. 9. Delivery Condition: Forged Bar; Semi-Finished; Finished Kelly.