Check out Climaware in Popular science December 23, 2014 20:22

Check out this article in Popular Science to see how the technology that powers Climaware was developed and get an idea of how this new technology works. 

http://www.popsci.com/technology/article/2013-03/tech-transfer-winter-woes-nanotech-cold-necks-knee-pain 

A band that can get hot and cold on-demand is far more convenient than squirming under a dripping ice pack.” – popsci.com