I do not rate the instrument per se. The company Testo provides (as always) a high-quality device, but it is not so available. The functions are limited to maximum and minimum current values. For this, the device is definitely too expensive. Quote of the product description: "Easy data transfer via USB cable, practical data analysis and documentation on the PC". This is definitely wrong. The device has a manufacturer-specific data interface, no USB interface. Only when one of approximately 100 euros !!! additionally buys a reader, the logger functions described are available. Therefore, devaluation mean.