Designed for a quick change between piloted countersinking and screwdriving functions. Supplied with multiple drill bit sizes including 2.38mm, 2.78mm and 3.18mm. Set consists of a variety of bits including magnetic S2 steel PZ1, PZ2 and PZ3 bits. Suitable for No. 6, 8 and 10 gauge screws. Swift flip over allowed by quick release chuck on the extension bit holder. 1/4"Hex shank fitted with a hex key for drill bit adjustment or replacement.