REON POCKET is a new type of wearable thermo device that can directly cool or warm the body surface of the body contact area. It can be used during summer or winter. You can set the temperature according to your needs using smartphone apps.
However, the negative experience I have is the Apps is currently availabe only at Apple Appstore Japan and you need to have a Japan account to be able to download it.
I used this during my traveling, and when I am outdoor during this hot summer that we have. It helps cool down the body temperature. I tried to set it to hot, and It is really hot. I also use it for a short period during the evening and it helps me relax.
It comes with a wearable neckband and also you can purchase a T-shirt with pouch to put the Reon Pocket.
The T-Shirt is a little expensive. But you can just sewed a small pocket at you back to fit the Reon Pocket in your favorite T-Shirt.