✅The digital large backlit LCD display screen make it easy to read and record the data, especially in the darkness. ✅Built-in Battery(3.6VLow power consumption rechargeable batteries,no need extra batteries) backup - allows meter to be moved (and viewed) without losing readings ✅Measures various parameters: power (W), energy (kWh), volts, amps, hertz, power factor and maximum power (W), time, days - kWh is vital as this is what your electricity bills are based on! ✅With electricity expense calculating, you can monitor which appliance cost the highest energy. With overload protect function, it more safe for you to use this item when the whole power exceeds the rated power of monitor. ✅ RioRand Plug Power Meter will your suitable choice. 30 Days warranty.If you are disappointed with it, we promise return your full refund without hesitation.