Swivl-Eze is the #1 supplier of 3-4" pin seating hardwareHere's why: The 3-4" system gives you outstanding economical performance; The design is proven by decades of experience; Posts are available as fixed, manually adjustable, or power-adjustable; Seat mounts, posts and bases available in steel, aluminum, or stainless steel; Offered in 15-18" or 24-30" adjustable heights; Threaded, Steel Pin;