Springfield Marine | 2-7/8" Series | Mainstay Heavy Duty Adjustable Height Pedestal with Slide Seat Mount | 14.75" -20.5" (1250321) - Cascade Depot
Springfield Marine Economy Adjustable Pedestal for Boat Seat - 12" to 18" - Walmart.com
Amazon.com : Wise 8WP21-18S Boat Seat Pedestal, Adjustable Height from 12" to 18", with Standard Seat Mount : Boat Seating Accessories : Sports & Outdoors