Silverline - 7PCE HEX SHANK DRILL SET - 819714 Seven 1/4" hex shank pilot drill bits for drilling pilot holes without undoing the chuck. Fits 1/4" hex shank, fits all standard bit holders. Not suitable for high torque applications. Sizes: 3.0, 4.0, 4.5, 5.0, 5.5, 6.0 & 6.5mm.