Springfield Plug-In 9" Round Base f/2-3/8" Post [1300750-1]Plug In 9" Round Base for 2 3 8" Post 9 Round Base With 8 Round Hole Pattern. Satin Finish, High Strength Aluminum. Below The Deck Mount, Requires 3 3 4 Hole In Deck. Use With Any 2 3 8 Plug In Post (sold separately). WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings. ca. gov.