4. This machine uses a 9V battery, you can open the back cover to replace the battery.The product principle diagram is as follows, the red and black meter pen is equivalent to the switch, when not measuring, the circuit is not on, no current consumption, a 9V battery can be used for 3-5 years. 2. use method, the machine be measured by the meter pen contact the two ends of the wire, if the machine issued a sound and light alarm, that the wire is conductive, the opposite is broken.On the contrary, it is a broken circuit. 3. Before the test, the meter pen of the machine be directly shorted, there is a sound and light alarm for normal, if not, please check the meter pen or battery is If not, please check whether the meter or battery is normal. 1. This machine is mainly used to dry test the wire and other conductors through and through, equivalent to a thousand multimeter through and through file, simple and convenient to use. 5. When the red and black meter pens are shorted, the circuit is on and the circuit current is about 30mA, this current through the product being measured, so this product is not suitable for measuring products with components, the 30mA current may burn out the components., Weight: 0.32959108169 Pounds, Manufacturer: Gishbjka