High Speed Steel Material: Made of good quality 4241 high speed steel, owns long service life. It has high hardness and is not easy to rust and will not break. Fast chamfering without burrs: The countersink drill bit set comes with fast, smooth and clean chamfering without burrs. Excellent Performance: The bevelling drill bit features stable structure, excellent performance and long service life. The 4-piece deburring tool set can remove burrs, metal processing and non-metal cutting. Parts under 25 degrees of difficulty: suitable for parts with a difficulty below 25 degrees, such as carbon steel, chopped iron plates, insulation plates and PVC plates. 4 Specifications: A total of 4 pieces in the package, come with different specifications, which will meet your different using needs. Item Type: Countersink Deburring Drill Bit Material: 4241 High Speed Steel Purpose: Suitable for workpieces with a hardness of 25 degrees or less, such as carbon steel, chopped iron plates, insulation plates and PVC plates SpecificationBlade diameter (approx.)Diameter of Applicable Hole (Approx.) Shank Diameter (Approx.) Overall Length (Approx.) 2-5mm10mm/0.4in2~5mm/0.1~0.2in6mm/0.2in45mm/1.8in5-10mm14mm/0.6in5~ 10mm/0.2~0.4in 8mm/0.3in 50mm/2in 10-15mm 21mm/0.8in 10~15mm/0.4~0.6in 10mm/ 0.4in 65mm/2.6in 15-20mm 28mm/1.1in 15~20mm/0.6~0.8in 12mm/0.5in 85mm/3.3in< /p> Package List: 4 x Countersink Deburring Drill Bit Note: 1. Suitable for materials with hardness less than 25 degrees. 2. Please allow a little size error due to manual measurement. Thank you for your understanding.