Size

Specification:
Type A Diameter: 10mm Weight: 90g length: 22cm
Type B diameter: 20mm Weight: 200g length: 22cm
Type C diameter: mm Weight: 280g length: 22cm
Type D diameter: mm Weight: 380g length: 22cm

The inner diameter of the iron ring at the end of the bit: 18mm




There is also a version with a 28mm inner diameter ring, you can go to buy