attwood SP-67739 Swivl-Eze Lock'N-Pin Stainless Steel 7-Inch x 7-Inch Non Threaded Boat Seat Pedestal Base Non threaded SP-67739 designed to accommodate 3/4 inch pin socket 7 inch square base requires a 2 3/4 inch diameter mounting Hole Stainless steel base features a satin finish, countersunk mounting holes, steel Lip tube and nylon bushing Engineered to exceed American boat and yacht Council standards Type B rating, not for Use as a helm/driver seat or for speeds in Excess of 5 MPH