Test batteries for remaining power in seconds! The Delkin Battery Tester can test AA, AAA, CRV3, 9V, CR-V3 and 2CR5 batteries accurately for remaining battery life. The only power required to run the tester is supplied by the battery inserted into the tester slot no adapters required. A switch allows the user to test either primary or rechargeable batteries, and LED lights quickly indicate how much power is remaining once a battery is inserted. The tester is designed to be small, lightweight, and portable so that it fits easily into your camera bag.