Specification:1. Product name: Digital battery tester2. Size: 2.48*1.14*0.7 inch3. Material: Plastic4. Color: Black / Red /Blue5. Certification available: CE, FCCDescription:1. The battery tester is suit for cell, button and watch type batteries.2. It is helpful in determining if the hearing aid is failing or if the batteries are dying.3. No batteries required for operation.4. There is a storage compartment for 2 spare hearing aid batteries.(battery not included)Operation:Place the battery on the gold colored plate, with the "+"facing up (usually the smooth side of the battery facing up) and then slide/push the battery towards the LCD screen to get a reading on the battery's strength. It will tell you how strong the battery is.Please notice that the test should be fulfilled within 2 minutes.