Spax 4101020500606 #10 x 2-1/2" Yellow Zinc Unidrive Flat Head Wood Screw (1 lb Box) Check out our Threads!! our patented thread technology allows the screw to be driven faster, is easier to install, and reduces splitting in wood. Let Spax take some of the hassle out of your next project Unidrive is a( Phillips/square combo) drive system for the Spax fastener. The user has the option of either using a Phillips drive bit or a square drive bit for installation Heat treated Grade 5 Durability. Subjecting the screw to heat treating gives greater strength and reduces breakage Patented MULTIhead countersinks the screw head flush in wood. Keep a smooth surface on your project for greater design and functional qualities This superior wood construction screw is coated with Yellow Zinc to protect the screw so your interior project will last