The Standard Post Mounting Flange is made from heavy gauge steel with the tube/sleeve sized to accommodate a 3” O.D. round post. This flange is designed to be surface mounted using appropriate hardware (not supplied) for the mounting surface (expansion anchors, lag screws, etc.). Please note: these flanges are not recommend for use with poles over 8’ or in high traffic areas. If a permanent mounting is required it is recommended that you use the direct bury method with a post at least 2’ longer and buried below grade and back filled with cement. Hole locations in the surface flange mounting plates may vary slightly from those indicated on the product specification sheet. It is suggested that you wait until you receive your mounting flange before drilling any holes at your installation location. Inverted mounting flanges are also available by special order. Call for details or if you have any questions regarding this product.