FastenMaster TimberLOK Framing Screw - No Pre-Drilling. Countersunk Head Style. Heat Treated for Strength. Heavy Duty Threads for Holding Power. Easy to Remove. The OMG TimberLok is designed to drive straight through pressure treated joists. For best results, use a high torque, low RPM 1/2 inch power drill. 5/16 inch Hex Bit Included. - Thread Diameter: 0.26", Length: 6", Head Type: Countersunk Hex Washer, Material: Carbon Steel, Finish: Epoxy Coated, Color: Black, Package Quantity: 50, Packaging Type: Box