The Blair step drills benefit from being made of premium cobalt M42 high-speed steel with a TiN (Titanium Nitride) coating which improves tool life. The step drills also feature an angled double flute which increases penetration rates and reduces the force needed when drilling. Starting the hole is made easy, thanks to the drill's split point. These step drills are available in the following sizes: No. 35400 for sizes 1/8" to 1/2" for 1/8" materials, No. 35401 for sizes 3/16" to 1/2" for 3/8" materials and No. 35402 for sizes 3/16" to 7/8" for 1/8" materials.