Wise 8WD015 Pilot Helm Chair Shell and Pre-Mounted Universal Mounting Plate Features Thick Wall Rotational Molded Plastic Frame with Plastic Injection Molded Universal Pedestal Mounting Plate with T-Nut Inserts. Molded Arm Rests. Mounts to any 4 Bolt BIA Standard Pedestal System. Roto Mold Seat Shell Only - No Cushions