SWIVL-EZE®LOCK'N-PIN BASE PLATE - STAINLESS STEEL FINISH w/STEEL LIP TUBEProven design. Patented Lock'N-Pin system is very safe & prevents unintentional detachment. Exceeds ABYC Standard H31.6.1. Description 6"x8" Non-Threaded Base w/Nylon Bushing. Req. Dia. Mounting Hole: 2.75". Depth Below Deck: 2.5"