Omega Products 12mm 4 Bar Set - For Boring HeadsBoring Head Bars & Boring Head Bar Kit 12mm, a versatile and reliable solution for your boring and milling needs. Our Boring Head Bars are made of hardened steel and precision ground to ensure maximum durability and accuracy. They feature a 12mm shank diameter and are compatible with most boring heads and machines, making them a versatile choice for a wide range of applications.