The voltage tester requires no power when it is working, which is safe and convenient to use. The voltage tester is designed with color coded display screen, which is easy and convenient to read. Made of ABS material, the voltage tester is lightweight and eco-friendly to use. The length of the voltage tester is 10.5cm, width is 6cm and thickness is 2.5cm. The voltage tester is suitable for testing many types of batteries such as C battery, D battery, AA battery, AAA battery, 9V square battery and so on. Item Name: Voltage Tester Material: ABS Features: Universal, Color Coded, Safe Size Details: 10.5cm x 6cm x 2.5cm/4.13" x 2.36" x 0.98" (Approx.) Notes: Due to the light and the screen setting difference, the item's color may slightly differs from the pictures. Please allow slight dimension difference due to the manual measurement. Indicator Light: Red: The battery needs to be replaced or recharged, that is, the battery is basically unusable. Yellow: The battery power is low, but can also be used in some household appliances. Green: The battery power is full. Usage: 1, The 9V battery is directly inserted into the two test holes on the side of the tester. 2, For other batteries such as AA battery, please open the test arm at the top of the tester with your hand, and insert the battery. Package Includes: 3 x 1 x Voltage Tester