Amazon.com : Boat Seat Pedestals and Bases Boat Pedestal Seat with Slide Swivel and Height Adjustments for Marine Boat Seats Captain Chair Fishing Seats 13.5 Inch to 18 Inch Height Adjustable Base :
Boat Seat Pedestals | Boatseats.com
Boat seat chair pedestal 100mm dia Heavy Duty - BUY HERE !!