Milwaukee 48-89-8990 3 Piece Step Drill Bit Set. Features With a single cutting edge design you will have more control and a cleaner finish Made of high speed steel these new step drill bits are durable and designed to drill through most metals The black oxide finish prevents corrosion and has great capacity to work with drilling lubricants With laser etched markings you will always know your hole sizes...no guess work The new speed start tip prevents bit walking and allows faster penetration 3-flat shank prevents slipping in the chuck High Speed Steel Make-up is ideal for cutting into stainless steel aluminum brass copper plastic and more. Includes 3 Piece Step Drill Bit Set - 48-89-8990 13 Hole Bit - 48-89-9100 9 Hole Bit - 48-89-9105 6 Hole Bit - 48-89-8955.