The Water Pillow's Fiberfill pillow is our Original pillow and offers you a soft layer of resilient Dacron Hollofil® fiber providing exceptional comfort for the head. The fiber floats on a thin layer of water for responsive support. The Water Pillow is clinically proven to reduce neck pain and improve quality of sleep. The Water Pillow is completely adjustable. Simply adjust the firmness of your pillow by adding (or removing) an amount water that provides the perfect level of support for you (soft, medium or firm). You won’t wake up multiple times every night to fluff and re-stuff your pillow because the Waterbase maintains the support by adjusting to your head motions.