Armeg Nail Proof Bi-Metal Woodbeaver Drilling Bit is designed with all the benefits of the original Wood Beaver, the Nail-Proof features a stronger cutting head, allowing it to provide effective drilling even after nail strikes. The robust profile of the four precision ground cutting teeth provides extreme resistance to hard objects whilst the HSS cutting head increases durability in tough materials to give longer tool life. Apart from 32mm which has a 7/16″ shank and can’t be used in impact drivers.