The Mainstay Adjustable Height Seat Pedestal Manufacturer: Springfield Marine; Part Number: 1250200-L; UPC: 038132915411 Materials: Aluminum; Overall Dimensions: 12 5/8" L (extending to 15 5/8") x 9" W x 9" D The swivel measures approximately 6 5/8" x 6 5/8" with standard 5" x 5" mounting pattern. The base is 9" in diameter with (6) 1/4" diameter mounting holes. Sold as seen in pictures; Note every computer shows colors differently; All measurements are approximate; Hardware and instruction/installation manual not included.