It is like a natural way to wake up, where you feel more rested and relaxed.
In the night you go through different sleep phases, during the different phases you move different in bed. The Natasch sleep alarm clock is able to use the accelerometer in your iPhone to monitor and determine which sleep phase you are in. In a 30 minute alarm window, which ends at your set alarm time, the alarm clock will wakes you in your lightest sleep phase.
You can use the Natasch sleep alarm for power naps too. Set your sleeping time for 15 to 30 minutes and the alarm clock will use a 5 minute alarm window then.
You can post your sleeping cycle on facebook as well.