Northern Industrial diamond coated drill bits provide extra strength that make these bits a good choice for auto repair, especially brake discs. Includes (qty.) 8 Diameter (in.) 1/8 to 3/8 Case Included No Additional Product Specs * Diamond coating * Extra strength makes these bits a good choice for auto repair, especially brake discs * Suitable for steel, cast iron and aluminum alloy applications * 8 bits in 1/8in. through 3/8in. Sizes