Gold Star interior multipurpose screws are for professional operations and demanding industries using hard or soft woods, chipboard and other tough or treated materials - an excellent general purpose fastener with a yellow zinc coating. Zinc coating on high quality, heat treated, hardened steelType 17 notched extra sharp point starts quickly without walking, reduces need for predrillingTiny cuts on threads cut through fibrous materials and greatly reduces the torque needed to drive the screw without affecting holding powerKnurled shoulder reams hole in board being fastened, reducing drag on shank and driving tool True flat head with 16 cutting nibs self countersinks and prevents spinout Deep, wide, sharp threads cut cleanly & easily providing maximum holding power