This is a very small traditional woman’s dress watch with a snap-on caseback you pop off with a watchmaker knife to replace the battery. You may want to have a jeweler or watchmaker do this for you. Don’t take it to the guys in the mall. The expansion bracelet is a potential problem. Chances are good you’ll replace it with an 8mm leather strap for a more comfortable fit, and the strap will cost $20+. 30M WR is okay for a dress watch, but there are more practical alternatives in this price range.