Manufactured from carbon steel. Useful in finishing & de-burring the holes. Heat treated for extra strength. Prod. Code range inch mm agrtr-140 18 to 12 3 to 12.7 mm agrtr-141 18 to 58 3 to 16 mm agrtr-142 532 to 78 4 to 22 mm manufactured from carbon steel. Useful in finishing & de-burring the holes. Heat treated for extra strength. Prod. Code range inch mm agrtr-140 18 to 12 3 to 12.7 mm agrtr-141 18 to 58 3 to 16 mm agrtr-142 532 to 78 4 to 22 mm