The Chillow is a non-electric heat-sink you put under your pillow to keep it cool at night.
The Chillow was designed to match your body's cooling needs. At night after an active day, when your metabolism is high and you're hot, the Chillow is cool and refreshing. But in the the early a.m. hours, when your metabolism is low due to inactivity, and air temperature is at it's coolest, the Chillow is lightly cool to lightly tepid, which is exactly the temperature you will enjoy. After you get out of bed, the Chillow loses any accumulated heat and recharges so it's ready to go again at naptime, or at bedtime. There is no maintenance required, save sweeping the air out once per month, which takes approx. 20 seconds.
(via Gizmodo)