GRK R4 self-countersinking screw with patented underhead cutting teeth that transport drill dust away from the screw hole while cutting a perfectly clean countersink. Climatek corrosion protection for interior and exterior use.

• #9 x 3-1/8" size
• 425 screws per box
• Star drive (T25 bit) resists cam-out
• Self-countersinking head - no pre-drilling needed
• Climatek corrosion protection
• Works in wood, composite decking, particle board, plastic, and sheet metal

Ideal for decking, stairs, and residential construction.