This is a special wristband, and it will keep you warm or cool. How? It uses a copper heatsink to fool your body into thinking that its being warmed or cooled without the ambient temperature changing.

Developed by the folks over at MIT, the wristband is called Wristify. It relies on rapid external temperature changes on a person's skin, which can actually affect how the whole body feels.

The wristband is powered by a lithium polymer battery for up to eight hours, and delivers rapid but subtle thermal pulses that change at the rate of 0.4 degrees celsius every second.

The thermal pulses will make the wearer's body feel as if it is getting warmer or cooler. This allows the wearer to be comfy without having to adjust the temperature or have a wardrobe change. [MITnews via Popular Science]