Review on dretec Waterproof Shower Timer - Officially Tested in Japan, Magnetic Backing, Silver Black Design, Includes Starter Lithium Battery by Juanita Riles

I take a cold shower and measure how long it stays cold. This is perfect for my needs. Magnetic backing makes it easy to stick to the top of the shower curtain and not easy to fall off. The timer function seems good, but I haven't compared it to an atomic clock. So if you're looking for absolute accuracy, you might need to do a little more exploratory research. It's definitely waterproof, I've showered over 20 times and it hasn't had any issues. It may wear out over time, but for now it's working great for me. It doesn't turn off (I can tell) but I haven't had any battery drain, I've had it running for over a month now. .It looks like a Japanese product, which doesn't bother me - its quality is higher than if it was from another country of origin.