Simpson Swan Secure S10250DXP Dexxter Composite-Decking Hand-Drive Screws 305 Stainless Steel 350 pieces. Unique thread form removes exhaust while driving to reduce “mushrooming” in composite decking. Type-17 point for fast starts and 6-lobe drive bits included in both contractor and deck packs. Pre-drilling recommended near board ends to prevent splitting. Simpson offers their Decking Screws in either Deck Packs of 350-count or Contractor Packs of 1750-count. Deck Packs contain 350 screws or enough to fasten 100 square feet when using 6-inch nominal boards on 16-inch centers. Contractor Packs contain 1750 screws or enough to fasten 500 square feet when using 6-inch nominal boards on 16-inch centers. Driver bit included in each package.