ITEM NAME:6pcs 3 Flute 90 Degree Hss Chamfer Cutter Bit Chamfering Countersink Dril RNG.Great for chamfering, deburring and countersinking. Three flutes design provides small chip loads and quicker removal. There are total six pieces of countersinks in sizes of 6.3mm, 8.3mm, 10.4mm, 12.4mm, 16.5mm, 20.5mm.