White Captains Helm Boat Seat With Armrest's, Stainless Steel Heavy Duty Boat Seat Pedestal, With Cast Aluminium 360° Positive locking Swivel Seat Base. Fully Adjusting Height 33cm - 48cm 
Tube dia 87mm, Base dia 230mm
Adjusts seat height 43cm to 58cm. 
Seat manufactured with a heavy duty marine grade vinyl providing durability against UV fading and mildew. The base is pre-drilled and threaded for mounting, standard swivel and pedestal, supplied with 4 fixing bolts. 
Seat dimensions: 
530mm deep 
670mm wide (to edge of armrests)
470mm high