W.L. Fuller C9 3/8" Type "C" Countersink for 3/16" Drill Bits 3/8" Countersink Diameter for 3/16" Drill Hole Diameter 7/8" Overall Length Used to countersink & counterbore for the heads of screws Designed for use in all woods, plastics, and non- ferrous metals Made of Carbon Steel and heat-treated for long tool life