Springfield Marine 1060407 Yachtsman 2 W/mounting Plate Deluxe pilot helm chair features rotational molded thick wall plastic frame with T-nut inserts for mounting. UV and mildew treated marine grade vinyl with embroidered logo. Snap on and off seat cushions have mesh underlay to expel moisture. High compression foam padding. Molded arm rests. Seat dimensions: Height 17", width 21-1/2", depth 16". Comes pre-mounted with injection molded plastic mounting plate. Mounts to any 4 bolt BIA Standard pedestal or 5-1/4" hole pattern mounting system.