It\’s high-precision internal resistance meter for rechargeable batteries, capable of measuring battery voltage and internal resistance of AA, AAA, 14500, 14650, 16340, 16650, 18350,18500 and 18650 batteries. The tester gives the most accurate readings.The device includes a rechargeable battery and a Type-C interface; it can be charged with any 5V charger. In the event of a power outage, LO is displayed on the LCD for 1 second. The button above the display is used to turn on or off the backlight. A 3-second long press will switch off the gadget. The device also has a sleep mode, which means that if no operation is detected, the device will go into sleep mode after 30 seconds.If the voltage or internal resistance of the tested battery is zero, this could be the result of inadequate connecting. Please replace the battery and remeasure it. Features : High precision Green backlight Integrated four wire battery compartment Large capacity standby battery & Super Long standby Small size & light weight & easy to carry Specifications : Modal Number IK00365 Product type IR tester Power Supply In-built rechargeable battery Voltage Measurement Range 0.5V to 9.99V Resistance measurement range 0-999m Accuracy 15% Backlight Yes Dimensions 156x63x36mm