Provided High-pressure Gauges can be operated with the smart-phones or tablets. These are essentially helpful in service as well as error detection on refrigeration & air conditioning systems, for their further installation. These compact as well as professional testo 549i high-pressure measuring instruments are capable to be controlled via the utilization of testo Smart Probes App. These can be operated by using smart-phone or tablets, and are appropriate for carrying out the troubleshooting as well as servicing on air conditioning and refrigeration instrumentality. The High-pressure Gauges also enable the automatic calculation of evaporation as well as condensation temperatures.