One. Engineered performance. Multiples materiales. No pre-drilling (Concrete and masonry applications require a pre-drilled hole that is 1/4 inches longer than screw length (see drill bit chart). In metal up to 20 gauge thick, no pre-drilling is required). Premium exterior coating. T20 Pro-Stik Bit included. 8 x 1 Inches. Wood. Masonry. Metal. Drywall. Plastic. Engineered for optimum performance in multiple materials, Power Pro One Screws are the One Screw you'll ever need! Flat Head - Easy & clean countersinking in wood. Star Drive - Star Drive and Pro-stik bit prevent cam-out and increase stability while driving. Spiral Flutes - Superior torsion & pull-out strength in wood and concrete. 1-1/2 inches & longer screws have this feature. Serrated Hi-Lo Threads - Increase installation speed while reducing drive torque. Pyramid Point - 3 sided point drives fast through wood and acts like a drill when penetrating metal up to 20 gauge thick. Recommended for exterior projects and treated lumber. Patented technology. Screw size: Number 8 (Drill bit size: 1/8 Inches), Number 9: (Drill bit size: 9/64 inches), number 10: ( Drill bit size: 5/32 Inches), number 1/4 inches: (Drill bit size: 3/16 Inches). Limited lifetime guarantee. www.hillmangroup.com. See www.Hillmangroup.com for product warranty information. Stackable. Reclosable. Reusable. Made in Taiwan.