A manifold gauge is a diagnostic and servicing tool used in HVAC and refrigeration systems to measure and control the pressure of refrigerant within the system. It typically consists of two pressure gauges (high-pressure and low-pressure), a manifold body with control valves, and color-coded hoses for connecting to the system. The tool helps technicians monitor refrigerant pressure, vacuum the system, charge refrigerant, and detect faults during maintenance or installation of air conditioners and refrigeration units. Durable and precise, manifold gauges are essential for professional HVAC servicing and repair.