Don't know what it is about this two-watch package of stopwatches. Cound not get either watch to stop beeping approximately every 15 minutes or so. Finally took the batteries out of each. When I put them back in, the stopwarch reset itself and the beeping stopped. I've been using stopwatches for more than 40 years, and this is the first time I've encountered such a weird one. By the way -- don't count on the instructions printed on the box; the appear to have gone through several layers or Google translator and likely will make little sense to English speakers. Some companies really do need to hire qualified translators.Does its job as a stopwatch, would have preferred it to also have a countdown mode instead of the clock/alarm feature. Seems like a wasted opportunity. The instructions were covered by "pass QR" tape but it wasn't that hard to figure out how it works with a little help from the instructions on the amazon page.As far as I can tell replacing the battery requires you to screw open the case, which is the opposite of the easy battery replacement promised, but I'm hoping they'll last a long time and won't need frequent replacement.I’m sure these are great if you are going to handle them gently, but in the hands of teenagers in a very quick amount of time, the upper left side button was stuck in and therefore not usable. They lasted less than a few days each.Reçu un peut en retard, un des chronomètre ne marche pas et il n'y a pas de fente pour changer la batterie. Aussinon l'autre fonctionne bien.Button very sensitive but good stopwatch overall