Features: 1. Set the time, temperature, voltage, three functions in one 2. Manual error correction function with a temperature setting range -5 Celsius  ~ 5 Celsius  Electrical Characteristics: 1. Input voltage 5 ~ 60V 2. Voltmeter range 5 ~ 60V, the measured voltage is the input voltage. 3. Temperature measurement ranges from -40 Celsius to 120 Celsius 4. Working current is about 30MA  How to use:   Keyboard plate has two keys: S (Setting), M (Mode); 1. Under normal use, press the "S", "minute" starts flashing, then press the "M", "minute" increases between 00 to 59 cycles. After setting "minute", press the "S", "hour" starts flashing, then press the "M", "hour" increases between 00 to 23 cycles. After setting "hour", press the "S", "date" starts flashing, then press the "M", "date" increases between 1 to 31 cycles 2. Then press "S", displayed AC: xx and Ac:xx, (AC means temperature sensor 1, Ac means temperature sensor 2. xx is the value to be corrected temperature value in degrees. Press the "M" to adjust the temperature error correction value, ranging from -5 ~ 5, a positive number is increased, the negative is reduced. After correcting the temperature error, and then press "S" to save all the data, and return to normal display.) 3. Then press "S", dd:0 means time + temperature 1 + temperature 2 + voltage, dd:1 means time + temperature 1 + temperature 2, dd:2 means time + temperature 1 + voltage, dd:3 means time + voltage 4. Then press "S", DF means cyclic display interval time.