La Crosse Technology 911-114 Portable Battery Tester
Don't throw away Good batteries.  Test them first. The portable battery tested by La Crosse tests one battery at a time. Test rechargeable or alkaline batteries in the following sizes: AAA, AA, C, D and 9V, the compact size allows you to carry the tester with you on the go in a purse, camera bag, luggage or backpack. Simple operation: Insert 1 battery and press down on the tester to check battery strength.