10 x 3-7/8 ProMax Wood Deck Screws, Unplated Steel, Flat Head, Square Drive - QTY:500 - 3ULC8

Whether you are building some great looking 2 x 4 furniture or doing a bit of light framing, ProMax™ Optimized Thread Length™ screws will make construction easier. The extra long unthreaded shank prevents cross-threading or jacking without the need for a clearance hole, and the 1/8" length system allows use of the longest screw possible without fear of backside protrusion. These Square Drive screws have self drilling auger points, self countersinking nibs, and have a light “lube” finish suitable for interior, non-visible applications. Made in China. #2 Square Recess. Unthreaded Length 1-9/16"

ProMax™ Optimized Thread Length™: What It Means and Why You'll Like It!
Deck screws are a good example of Optimized Thread Length. The screws normally used to install 2 x 4's or 2 x 6's for decking are 3 inches long and have 1 inch of unthreaded shank. Since 2 x 4 and 2 x 6 deck material is 1-1/2 inches thick, the threads bridge the joint, as shown, resulting in an uneven and unsightly surface, or screws that are over-driven trying to “pull the board down.”
ProMax™ screws are different: Thread length is optimized to eliminate crossthreading, and the 1/8” length system allows use of the longest possible screw. In most cases, the smooth shank and self-drilling point allow installation without predrilling! Just select a screw that provides an unthreaded shank length equal to or slightly greater than the material thickness being fastened.