Volvo Penta 4 Cylinder B230 AQ 131, 151, 230, 250 Heat Exchanger Insert 855555. In excellent used condition with no cracks or leaks. Pressure tested. This is Larger chamber insert with 9 chambers for the AQ171 but will fit AQ131, 151, 230, 250 SOHC Engines. But can be used on a 151 with a smaller backing pad and would become a small upgrade from the 7 fin.