The hss drill bits are gripped by a spring steel collet into the hex shaft the hex shanks snap into the quick chuck the hex collar is supplied in the sets to enable drills to be removed with two spanners whats included1 x 1mm drill bit1 x 2mm drill bit1 x 3mm drill bit1 x 4mm drill bit1 x 5mm drill bit1 x 6mm drill bit1 x 7mm drill bit specifications shank diameter14 inch hex