Working as intuitively as on a smartphone - this is made possible by the testo 558s digital installation aid. The touchscreen operation makes configuration, control and documentation even easier. Alternatively, the device can be operated entirely via the testo Smart App or via buttons for employees wearing gloves. To make everyday work even easier, the measurement results can be shown on the large colour display in clear graphics and as 30-minute trend curves. A 72-hour long-term measurement is also possible with the integrated data logging. The high measuring accuracy of 0.25 % full scale also enables reliable evaluations. Thanks to the large number of stored measurement menus and connectivity across the entire Testo refrigeration portfolio, any application can be controlled via the installation aid. For maximum safety, the installation aid is compatible with flammable refrigerants of classes A3 and A2L. With over 96 refrigerants stored in the installer aid and regular updates, the installer aid is always up to date.