Ideal for cleaning out corrosion build up, oil residue from head gasket leaks & water pump debris build up. Universal fitment - The kit includes adaptors for large bore main hoses & smaller heater matrix sizes. Adaptor sizes: 17mm & 20mm heater hose barbs, together with a small conical adapter for flushing heater matrix. Includes built in back pressure control valve to prevent air pressure pressurising the water feed. Combine water, air pressure & pulsations for better cleaning.