ALLOSUN BT2 Battery Tester for 9V 1.5V Easy-to-read color-coded display with "Good", "Low" and "Replace/Recharge" indicators The battery tester allows you to check the charge of 1.5 volt and 9 volt quickly and easily. Mini size , quite easy to carry.It is practical and easy to operate. It can be used for AAA,AA,C,D,6F22 batteries and so on. Compact design. No batteries required to operate.