Designed for long-lasting results in the toughest materials, Alpha Gold Series countersinks last three times longer than other countersinks on the market. Fully ground M2 HSS-CoB increases strength and countersink life Titanium nitride coating reduces heat and increases lubricity for extended life 3 flute design provides clean and fast countersinking and deburring with a cordless drill HSS cobalt with TiN coating 1/4" quick change shank Suits: Non-hammer action portable power and pedestal drills Technical data: Head diameter: 19mm, 3/4 Overall length: 45.5mm Shank diameter: 1/4" Range min-max: 4 - 19