9 x 3 1/2 Simpson Trim-Head Wood Decking Screws - Square Drive 305 SS- 5 lbs Pack (310) . The type 17 tip provides fast starting and resists splitting in hardwood. Coarse threads run approximately 2/3 up the shank to draw the decking tightly to the substrate. Pre-drilling is recommended near board ends to prevent splitting.
#1 Square Drive - All #7 diameters and 9 x 3 1/2
#2 Square Drive - 9 x 4
