Features Most suitable for DIY, home and general construction or engineering use, helps a lot The tip of the 135 degree separation point can achieve perfect centering and reduce drilling pressure Suitable for drilling steel, stainless steel, aluminum, copper, and many other materials Made of 95% high speed steel and 5% cobalt material, more heat resistant, and very durable There are 13 specifications in total, which can meet your needs in different scenarios, and the product length ranges from 3.7cm to 10cm Specification: Item Type: Twist Drill Bits Material: 95% High speed steel + 5% cobalt Product Length: Approx. 3.7 ~ 10cm / 1.5 ~ 3.9in Product Specifications(metric): Approx. 1.5mm / 0.06in 2mm / 0.08in 2.5mm / 0.1in 3mm / 0.12in 3.2mm / 0.13in 3.5mm / 0.14in 4mm / 0.16in 4.5mm / 0.18in 4.8mm / 0.19in 5mm / 0.2in 5.5mm / 0.22in 6mm / 0.24in 6.5mm / 0.26in Package List: 13 x Twist Drill Bits 1 x Storage Box Package List 13 x Twist Drill Bits 1 x Storage Box