Description Features: - Lightweight and easy to use,practical and versatile. - The instrument has a variety of uses, measurable 1.5V battery(AAA, AA, C, D and so on), 9V battery - Small size and easy to carry. On-off Test: - 1.Take the black test wire to the left jack and the red test wire to the right jack. - 2.Connect the probes of both test wires to both sides of the circuit under test. - 3.If the resistance of the circuit under test is less than 500 , the built-in buzzer of the instrument will ring. If the resistance of the tested resistor is between 500 and 1 k, the built-in buzzer of the instrument may or may not sound. Note: Before testing, disconnect the power supply of the circuit under test and fully discharge all the capacitors. Note: - Do not place the instrument and battery in places where babies and children can get it. - If the battery is dead or not used for a long time, remove the battery from the battery compartment of the instrument. - Do not put the battery into the fire,do not reverse the positive and negative of the battery. - For different instruments, the required battery level is not the same.