CasioWatch with Movement Japanese Quartz Movement w-800hg-9av 35 mm

Dry heat, humidity, sweat, and all. While most modern digital watches are marketed for running, swimming, or military-style wear, this humble Casio thrives where you’d least expect: on the slatted bench of a 90°C Finnish-style sauna, where metal bands burn your skin and delicate electronics fail fast. This one doesn’t.I initially worried about chemical leakage in the sauna heat, so my friend—an expert in materials engineering—helped me run repeated high-temp sessions and surface wipe tests, confirming the Casio remained fully sealed and safe throughout.It’s incredibly lightweight at 37g—so much so that I forget I’m even wearing it. That makes a huge difference when you’re lying down and trying to relax. No cold metal, no dragging feeling on your wrist, no discomfort even when skin is damp or sticky. The resin strap is soft and pliable and doesn’t absorb sweat. It dries fast and doesn’t develop odour over time, even with repeated sauna use. I just rinse it in water afterwards and hang it with my towel.What’s truly impressive, though, is how well this watch copes with heat. I’ve worn it during repeated 15–20 minute sessions in a 90–95°C dry sauna, and it's never once glitched, fogged, or shut off. That’s a tall order for any battery-powered device. I wouldn’t submerge it in boiling water (it’s water-resistant to 100m, not steam-rated), but for dry heat? No problem. I don’t like taking my phone into hot rooms or relying on wall clocks, so this gives me full control over my session timing—down to the second with its built-in stopwatch.The digital display is large and legible even in low light. I use the backlight button when it’s darker in the sauna or early morning. The screen isn’t cluttered: it gives me the time, day, date, and the secondary time zone if needed. The stopwatch is very easy to start and stop, and the buttons are nicely tactile. No fiddling required—just simple, intuitive function. I’ve never had a missed press or delay, even with wet fingers.Battery life is supposed to last around 10 years, and given Casio’s track record with these movements, I believe it. No charging, no cables, no smart gimmicks to fail—just straightforward Japanese quartz reliability. The buttons don’t feel mushy or soft like cheaper knockoffs. They click with precision, and the strap buckle is solid enough to feel trustworthy, even when adjusted tight.I also appreciate the low profile. At 35mm, the case is modest by today’s standards, which makes it ideal for more discrete use. It fits neatly under a cuff, doesn’t catch on towels or clothing, and sits close to the wrist without wobbling. The acrylic screen does scratch a bit over time, but I prefer that to cracking, which glass faces tend to do when exposed to impact or stress—like temperature swings. For this reason alone, I’d take this over a Gorilla Glass or sapphire crystal model for sauna use.In day-to-day wear outside the sauna, it’s just as dependable. Whether I’m out walking, in the garden, or doing DIY work, I never worry about it getting knocked or wet. The water resistance holds up in the rain and even in the shower, and the alarm is loud enough to wake me up reliably. The dual time zone feature is a bonus when I’m travelling between the UK and Europe and want to keep track of both zones.If I had to nitpick, I’d say the design is unapologetically utilitarian. It’s not trying to look like a fashion watch or something you’d wear to a dinner party—but that’s also part of the charm. It’s function over form in the best way. The orange-accented screen adds a bit of personality, and the strap holes don’t wear out or stretch over time. In short: it’s not pretty, but it performs.Would I wear it to a wedding? No. Would I trust it with my timing during a sauna detox session or icy plunge recovery afterwards? Absolutely. In fact, I’ve now bought a second one as a backup—though I doubt I’ll need it anytime soon. If you value comfort, simplicity, durability, and excellent timekeeping under extreme conditions, this is the best under-£20 watch you’ll ever own. It’s the ultimate sauna-safe digital timepiece—no fuss, no gimmicks, just solid old-school engineering that gets the job done.

Even better than I was expecting. Delighted with the watch. Great delivery and packaging. A+