Small and portable: simple and effective small aa aaa battery tester (BT-168D), compact and light, easy to carry. Test different battery types: The battery checker tester is suitable for standard and rechargeable household batteries. AA, AAA, C, D, 1.5V, 9V, button battery tester. Operation without battery: easy to read, numbers indicate the performance level. No battery is required. It is activated by the tested battery. Easy to read: The design of a portable handheld device Easy to read: the battery voltage value is displayed on the LCD screen. Save battery: you can just test the battery voltage to see if the battery capacity is low or high, which prevents us from wasting a perfect battery by throwing away a good one.