This is a Neck support pillow that is very customizable. It is construted with a core of figure 8 foam, where one of the humps is bigger than the other. This allows you to sleep on your side or your back. The outer zippered cover (washable) is filled with a fine Faux Down poly fiber so that it provides a soft contour for the head to sink into the foam.You can choose the firmness of the foam, as well as buy additonal piece of foam so can change out the foam and experiment. If you are a chiropractor fell free to contact us 877-3745569 9am to 5pm EST., we can set you up with several firmness foam inserts, that will save time in determining the right foam for your patient. We realise that proper neck support is crucial to sleeping properly. It can affect proper breathing as well as spinal alignment. The pillow fits into a standard size pillow case.