Measuring apparatus; current supplies including current sources; pressure detectors; trouble indicators; control instrumentation; test vehicles for water plants; heating plants and environmental protection services, which contain flow detectors and flow analyzers, including transducers; pressure test equipment and pressure transducers; electrical test and acquisition equipment for flow measurement and pressure measurement; power supplies; movable and portable test instruments for the exact determination of damaged pipes; gas detection and gas leakage instrumentation; water leakage detectors; slide damper and linkage search devices; line locator for the location of metallic lines and synthetic material lines; leak locator for the location of water pipe breaks; leak locator for the prelocation of water pipe breaks; slide damper locator for the location of hidden slide damper; pressure detectors for the measurement of the working pressure in the pipping.