Precision screwdriver set made of chrome nickel molybdenum steel professional quality rotating head and corrugated shaft inserts with 2 identical blade ends each 80 mm long blade width 06 07 08 10 11 12 mm blades are made of steel and are kept in place using a collet chuck rotating head and corrugated shank inserts with 2 blade ends each 80 mm long blade width 06 07 08 10 11 12 mm