the Universal: about 6.35mm/1/4 inch hex shank, ideal for electric hammer drills converting impact drill bit and quick change drill bits Size: Input connecting rod general handle 0.3mm-6.5mm hex; Classic 3-jaw design securely holds a wide range of twist drill bits Versatile use on impact drills and electric motor to change tasks quickly and keep the job moving Constructed with all metal for supreme longevity. NOTE: The product can NOT be used counterclockwise! Color: 2 Pack - 0.3 - 6.5mm Feature: Color: Silver and Black; Driver Shank: 6.35mm (1/4 inch) Hex Shank Clamping Range: 0.3-6.5mm NOTE: It can NOT be used counterclockwise!! . Package Included: 1 * Silver Keyless. 1 * Black Keyless Chuck. Chuck