Features: No more guess which batteries to keep and which to throw away, a quick and simple step to test them. Place your battery in the check compartment of the battery tester, and the easy-to-read display will tell you instantly whether you have a dud. No batteries required. It is activated by the battery being checked. Checks power level of almost all 1.5V 9V batteries. Compact size and lightweight, easy to carry. A must buy for anyone who uses regular or rechargeable batteries on a regular basis.