The Steadicam Smoothee is designed to give a steady, hand-held look to videos taken with iPods, iPhones, and GoPro cameras. With a little bit of practice, you can get a steady shot of anything that moves. So follow someone down a hallway, down a sidewalk, or up a set of stairs, without bouncy, shaky video.
Steadicam’s Video Manual explains it further:
Steadicam Smoothee for iPhone 5 or GoPro available at B&H Photo Video