... HRC PIN standard 1) American type sledge hammer: 4oz, 8oz, 12oz, 16oz, 20oz, 24oz, 32oz, British type Claw hammer : 21mm / 23mm / 25mm ... , 18mm, 20mm, 22mm, 25mm 5) Engineers' ball pein hammer: 4oz, 8oz, 12oz, 16oz, 24oz, 32oz, 40oz, 48oz6) Double faced smiths' hammer: 2lb ...