GRK R4 HandyPak Multipurpose Screws, 10 by 3-1/2-Inch, 50-Count #6 and #8 screws use T-15 bit; #9, #10, and #12 use bit T-25 Self-tapping, countersinking head; W-Cut thread design One package contains 50 screws Climatek coated for all weather corrosion protection conforms with ICC#2442 For use in wood, particle-board, cement fiberboard, plastic, and sheet metal