Draper Plain Slot Insert Bit, 5.5mm, 1/4" Hex, 50mm Long (Pack of 5)

Amazon

Chrome vanadium steel hardened, tempered with a shot blasted finish 64272 Item height-5.31 inches Item length-0.71 inches, Weight: 0.15 pounds, Manufacturer: Draper

Electrical World

Chrome vanadium steel hardened, tempered with a shot blasted finish. Supplied in 1, 2, 5 or 10's. Display packed.