Got these as a replacement battery for my Luminox Chronograph watch. As with most "precision" (I say that loosely only because most battery powered analog watches do this) I started notice it was losing time by a few minutes a day, and that it would tick a few seconds, wait, and then "catch up." All generally leading to a battery on it's end life. Bought these based off the number on the battery that was in my watch, swapped it out and now I'm back in business. Can't say how long the battery will last but I got about 5ish years from the factory battery so I'm expecting similar results from this. Plus for the price on a 5-pack of batteries I'll be able to have the watch going a long time, pending I don't break the watch first.