●Product parameterProduct name: Straight groove step drill bitMaterial: High speed steel 6542 (suitable for workpieces with a hardness of generally, such as iron plates, plate thickness below 5mm)Metal drill bits for steel have 4-12mm/4-20mm/4-32mm/4-40mm/10-45mm●Package include:4～32mm: 1 x Straight groove Step drill bits4～40mm: 1 x Straight groove Step drill bits10～45mm: 1 x Straight groove Step drill bitsOne Set: 3 x Straight groove Step drill bits(4～12mm/4～20mm/4～32mm one of each)●Note:1.When HSS-M35 drills 304 stainless steel:The thickness of 1mm can be operated with a hand electric drill, and the power is above 800W.The thickness of 2-5mm is recommended to use a bench drill for operation, and the speed is below 500 rpm.2.When working with step drills, it is necessary to add water to keep the temperature down.3.The pictures may not reflect its real color due to the computer display and light, please in kind prevail. Please think over before you buy it, thank you.