Square Drive Trim Head Exterior Coated Screws: A countersunk flat head of a width 1/3 less than a standard bugle head drywall screw. Has a recessed sguare drive. The last few threads of the screw taper to an extra sharp point with a groove cut out (Type 17 Point) which enables the screw to drive better without pre-drilling a pilot hole. Coated for exterior applications, including decks, siding and gazebos. Approved for pressure treated lumber. Minimizes the chances of splitting the wood, good for attaching trim or fence railings.