https://www.cnet.com/news/2018-winter-olympics-team-usa-heated-jacket-ralph-lauren/

It doesn't beep or light up. There's no buzzing or distracting alerts. It doesn't even feel like you're wearing a gadget. It's just smarts woven into your clothes.

The heated panel is made up of conductive inks, bonded to the inside lining on the back of the jacket. It's thin and flexible, and can be crumpled and washed.