Now that you've grown up and no longer live with your parents, the chances are good that you no longer have someone around telling you to stand up straight and not slouch. That might seem like a good thing at first, but once you start ignoring your posture you start turning into a hideous hunchback, and no one wants that.
The iPosture is a small device that's designed to be clipped to clothing or adhered to the skin. When it senses that you aren't sitting or standing with a straight back, it'll vibrate until you do. Once you wear it for a while you should start standing with proper posture automatically, making the iPosture unnecessary after a time. Now stand up straight, young man!