Springfield Taper-Lock 9" - Round Surface Mount Base [1600010]Taper Lock 9" Round Surface Mount Features: 9 Surface Mount Base, 8 Hole Pattern High Strength Aluminum To Withstand All Conditions Surface Mount Does Not Require A Hole In Deck Use With Any Taper Lock 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.