I have three flashlights that use D size batteries; they are used all year round when the power goes out or I need to get something out of one of the closets. Because these specific flashlights aren't used on a regular basis I need to buy batteries that are going to have a long standby life and not leak. I made the mistake of buying regular D size batteries and didn't use one of the flashlights for about four months and when I went to use it there was almost no power left to them. Have that happen when the lights go out and that's the last time that you make that mistake. The Advanced Formula Energizer Alkaline series is made for long standby life; they are great to have for seasonal use but you should check your flashlights on a regular basis if you live in an area where you lose power often. In the summer we lose power on an almost weekly basis when everyone is running their air conditioners or a transformer blows up. Sometimes there are accidents near a transformer and they need to be turned off for the power company to work on restoring downed lines. I like that the expiration date is stamped on the outside of the package; if I get them when they are on sale I can rotate them to use the oldest ones first. They are normally sold in a two-pack but the flashlights that I have require four D size batteries. I have never been disappointed with these since I switched to them; they have consistently worked any time that I have reached for a flashlight when the power has gone out or we've blown a fuse.