It comes down to our perfect pillow “recipe” based on more than 50 years and helping millions of people find their ideal fit. You start with just one choice based on the size you need for your bed: Low Profile or High Profile. High Profile is best for larger body frames and side sleepers, and Low Profile is usually optimum for front, back and other sleeper types. Our amazing BFF hybrid fill is adjustable, so you can remove or add fill as needed. (We ship extra fill for free!) And it's incredibly sculptable, meaning your Parallel Pillow is easy to shape and adjust right under your head and neck, which is the best way to support your position of the moment!