The Mediflow Waterbase pillow, which also comes in a Down Plus Version, is the only pillow clinically shown in 3 independent clinical studies to improve sleep and reduce neck pain. In fact, in a study at Johns Hopkins University, the Mediflow pillow ranked best in all 5 categories studied over all other pillows tested. Most importantly the Hopkins study found that subjects in the study with chronic neck pain reported a reduced intensity of pain after sleeping on the Mediflow pillow. The pillow can be adjusted to the userÕs preferred support level by simply adding or removing water.