Casio Computer Co. has released a new wristwatch designed to withstand temperatures of up to 100 degrees Celsius, making it suitable for use inside saunas.
Named “Sadokei,” the watch features a heat-resistant battery and a moisture-resistant resin body. It also comes with Casio’s first-ever stretchable watchband, making it easier to wear and remove in hot, humid environments.
A key feature of the Sadokei is its “sauna mode.” When activated, the watch’s large hand completes one full rotation in 12 minutes instead of the usual 60, helping sauna users keep track of standard session durations without complex settings.
The Sadokei is available in two designs — a white dial with an orange band and a black dial with a black band — priced at ¥16,500 (including tax). It can be purchased through online stores and electronics retailers across Japan.
According to Casio, the product was inspired by young employees who were frustrated by not being able to check the time during sauna sessions.
A team of four developed the watch over three and a half years, with the concept gaining early popularity. During a presale on a crowdfunding site in December 2024, all 2,200 units sold out within nine minutes.
Casio’s launch marks another step in its effort to combine functionality with lifestyle trends, appealing to Japan’s growing sauna culture.
