These 2 1/2" length #2 Phillips drive Flat Head ZINC PLATED particle board woodworking screws are #9 diameter ASYMMETRICAL THREAD. Zinc plated is a plating that is applied electrically to fasteners that prevents oxidation of steel by forming a protective barrier. FLAT HEAD with countersinking NIBS create a smooth flush finish. Asymmetrical thread pattern resists material slippage during pull out and vibration resulting in superior holding power. Type 17 point (also known as Auger Point) is a thread cutting screw for wood with a coarse tapping screw thread and a special long sharp point fluted to capture chips which provides no predrilling and reduces wood splitting. Each box contains approximately 2,500 screws (24 pounds)