We (me and my wife) absolute love this, and my wife basically stole this from my LeanRite. It's an ultimage calf/foot massager you can use on your bed.. haha. It work very well on LeanRite too, and it makes you lean back more (which is good for your posture).
I feel very spoiled. This works great with the chair and without the chair, with heat and without heat. Not just for your back. The instructions show you that it can be used for any part of your body (neck, shoulders, hamstrings, calves, etc...).