Description Seat swivel top and base with a 73mm diameter pedestal post. The swivel top is made from cast aluminium and powder-coated grey, and the base is made from marine-grade anodised aluminium. Features: Base: 228mm Height: 135mm Post: 73mm Rotates 360° Tightening knob is to clamp and tighten into position Non-locking Standard 7"x 7" seat mounting hole pattern