Thexton’s Cooling Systems Backflush Tool, No. 356, fits 1/2”, 5/8”, and 3/4” heater hoses, and uses a standard garden hose for water. The basic garden hose hook-up cleans cooling systems and heater cores without disassembly. No need to use acids or caustic solutions. The radiator pressure cap prevents over-boosting. This tool saves costly replacement of even the most stubbornly clogged heater cores. Made of corrosion-resistant aluminum.