--SMALL & PRACTICAL - Simple but effective battery tester checker for home (BT-168) , compact size and lightweight,easy to carry BATTERY TESTER FOR ALL BATTERIES - The universal battery tester works with standard and rechargeable household batteries: AA, AAA, C, D, 1.5V,9V and button type REQUIRE NO BATTERY TO OPERATE - Easy-to-read ,the analog display needle moves on a color-coded, calibrated scale to quickly identify "good" (green), "low" (yellow), and "replace/recharge" (red) battery status. No batteries required.It is activated by the battery being checked PERFECT FOR HOME USE - Great small battery tester can tell you if your battery is good, low, or needs to be replaced.--SAVE BATTERIES - You can simply test battery voltage to determine whether the capacity of the battery is low or high. It won't directly detect the battery capacity precisely. This will keep us from wasting perfectly good batteries by throwing out good ones