The Evacut Long Series Drill offers longer flute and overall length than standard drill bits. Ideal for drilling depper holes. The Black Jet finish is a specialist steam tempering process, which produces a Ferrous Oxide surface coating. This allows coolant or other lubricant to better adhere to the drill reducing friction and heat during drilling. Ideal for drilling ferrous metals such as steel, stainless steel, high tensile steel, alloy tool steels and cast iron.