@ai6yr Low-power cooling device for sleeping during hot weather. Runs off USB.
"The Flowing Water Mat Lite is a thin mattress pad with water continuously circulating through it. As your body warms the water beneath you, it returns to the unit, where it's cooled and sent back through the mat. The idea is to avoid one of the biggest problems with ordinary cooling mats, which is that they eventually warm up. It uses just 6W of power, runs via USB and includes a 1.7-liter water tank, three cooling modes and a timer that can be set for up to 12 hours."
https://www.engadget.com/2262963/cool-japanese-gadgets-not-typically-found-in-united-states/
@bbdd333 Oooh, fabulous... wonder how these would work deployed en-masse for heatwaves.