Description 1Countersinks are made from good speed steel which ensures a long service life 2There are total six pieces of countersinks in sizes of 6.3mm, 8.3mm, 10.4mm, 12.4mm, 16.5mm, 20.5mm 3Great for chamfering, deburring and countersinking. Three flutes design provides small chip loads and quicker removal 4They can discharge chip more rapidly and smoothly in the process of using 5Suitable for board of low hardness(less than 25) such as aluminum, wood, plastic and other soft material Features: Countersinks are made from good speed steel which ensures a long service life. There are total six pieces of countersinks in sizes of 6.3mm, 8.3mm, 10.4mm, 12.4mm, 16.5mm, 20.5mm. Great for chamfering, deburring and countersinking. Three flutes design provides small chip loads and quicker removal. They can discharge chip more rapidly and smoothly in the process of using. Suitable for board of low hardness(less than 25) such as aluminum, wood, plastic and other soft material. Specifications: Material: HSS Flute: 3 Head Diameter(mm) 6.3 8.3 10.4 16.5 20.5 Shank Diameter(mm) 5 6 6 10 10 Length(mm) 37 40 39 47 47 Package Includes: 6pcs x Countersinks