This particular device, which is of Chinese manufacture, is identical to other brands sold at a much lower price (possibly without a reputable warranty). It should be noted that the device is quite bulky. The included showerhead is of poor quality (so much so that at first I thought it was fake and left it in the box). The specifications state a maximum temperature of 40C, but in practice there is no limitation, and if the water flow we choose is very low and the water at the inlet is lukewarm due to summer, it can reach temperatures of 70C+. Like all these devices, this one also does not mix hot and cold water, so the desired temperature can only be achieved at a specific flow rate, depending on the temperature of the incoming water. In other words, you can have either a stable temperature or a stable flow, but you cannot adjust both to your liking. To make it perfectly clear, even in the summer, if you open the faucet fully intending to take a shower, the water will be barely warm, while if you let it run with a very low flow, it will be hot. Similarly, in winter, with an outside temperature of 5C, the water reached 20C with the faucet fully open and 45-50C with very low flows, but they were so low that it was not possible to take a bath, although they would be sufficient for a kitchen sink. In summary, it is sufficient for a shower only during the warm months, while during the rest of the year it is only suitable for "breaking" very cold water, for washing dishes and hands. Anyone with higher demands would be better off looking for a device with higher power, provided that their electrical installation can handle it. Surprisingly, this particular device has been working so far on a socket with a 10A circuit breaker that secures the "lighting" line (i.e., with a 1.5mm² cable from the main panel), which sometimes trips after about 20 minutes of continuous operation (circuit breakers can handle significantly more current than their nominal value for some time, but as time passes, this decreases depending on their curve). However, it is correct to draw power from a "reinforced" line (i.e., with a 2.5mm² cable and a 16A circuit breaker) to prevent the cable from overheating and to operate smoothly. For water heaters with a power greater than 3.5kW - maybe under certain conditions 4kW - a 4mm² cable is required and so on.