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!;Large, clear LCD display for easy reading(screen dimension: 45mm x 70mm). Cumulative Kilowatt-Hour Monitor. Calculates electricity expenses;Electricity price setting by pressing COST, FUNCTION, UP and DOWN button according to the instructions;Sets electricity price value which ranges 00.00COST/KWH ~99.99COST/KWH. Displays volts, amps and wattage accurate to 3%. Low power consumption.;Built-in battery(3.6V rechargeable batteries ) backup - allows meter to be moved (and viewed) without losing readings.