Item Type: Countersink Deburring Drill Bit Material: High speed steel 4241 Purpose: Suitable for workpieces with a hardness of 25 degrees or less, such as carbon steel, thin iron plates, insulating plates, and PVC plates SpecificationBlade diameter(approx.)Applicable hole diameter(approx.)Shank diameter(approx.)Total length(approx.) 2-5mm10mm / 0.4in2 ~ 5mm / 0.1 ~ 0.2in6mm / 0.2in45mm / 1.8in 5-10mm14mm / 0.6in5 ~ 10mm / 0.2 ~ 0.4in8mm / 0.3in50mm / 2in 10-15mm21mm / 0.8in10 ~ 15mm / 0.4 ~ 0.6in10mm / 0.4in65mm / 2.6in 15-20mm28mm / 1.1in15 ~ 20mm / 0.6 ~ 0.8in12mm / 0.5in85mm / 3.3in Package List 4 x Countersink Deburring Drill Bit 1. Suitable for materials with hardness less than 25 degrees.2. Please allow tiny size error due to manual measurement. Thanks for your understanding. 1Quick Chamfering Without Burrs: Countersink drill bit set come with quick chamfering, smooth and clean without burrs 24241 High Speed Steel Material: Made of good quality high speed steel 4241 material, possess long service life 3For Workpieces Less Than 25 Degrees Hardness: Suitable for workpieces with a hardness of less than 25 degrees, such as carbon steel, thin iron plates, insulating plates, and PVC plates 44 Specifications: A total of 4pcs in the package, come with different specifications, which will meet your different using needs 5Excellent Performance: Chamfering drill bit come with stable structure, excellent performance and long service life