With Japan sweltering through some of its hottest temperatures ever recorded this summer, more and more people are reaching for extra layers of clothing in a bid to keep cool.

If that sounds like a contradiction in terms, the growing popularity of jackets fitted with battery-powered fans that circulate air over the wearer’s body suggests otherwise.

First developed by Tokyo-based company Kuchofuku Co. Ltd., fan-fitted clothing has become a big hit with construction workers and other outdoor laborers since it launched in 2004.