The Watts No. TK-9 Model ?A? Backflow Preventer Test Kit is a compact portable testing device made for testing all Reduced Pressure Zone Backflow Prevention Assemblies and Double Check Valve Assemblies. The TK-9A is easily connected to any RPZ device enabling accurate testing of zone differential pressure, relief valve opening differential, fouled check valves or similar problems that visual inspections cannot locate. The unit is supplied with a rugged carrying case for easy handling and accessibility.