FOMI's Water Pillow will ensure that you get a good night’s sleep to rest, recover and prepare for the next day. Its outer layer of high-count cotton threading gives a soft, smooth, hotel quality feel that stays cool and comfortable all night. The inner layer of soft, fluffy polyester fiber provides maximum comfort. Finally, the water layer ensures that the pillow maintains its shape as well as instantly adjusts to your head movement, providing the ultimate, long-term, responsive support for the head and neck. This not only improves the quality of your sleep, it minimizes sleep interruptions. Clinical trials found that water pillows reduce morning pain intensity, increase pain relief, and improve quality of sleep. FOMI's Water Pillow is designed to support your head, neck, and upper back, preventing strain and injury. It allows the head and shoulders to be at a more comfortable and natural level and posture, relieving neck/cervical pain and swelling related to pinched nerves, neck strain or injury, herniated disc, degenerative disc disease, stiff neck, headaches. . The pillow can be easily adjustable to your personal preference. It can be soft, medium, or firm. Simply add more water for a firmer pillow, and less water for a softer one. For a softer feel, add about 70 oz of water. For a medium feel, add about 90 oz water. For a firm feel, add about 120 oz water. Then push your hands down on the bottom of the pillow to remove air pockets. Finally, screw the valve into the opening. IMPORTANT - In order to prevent leaking, please make sure to use the bottom of the funnel that comes along with the product to tighten the valve as much as possible. At 26"X 17", FOMI's Water Pillow accommodates back, side or stomach sleepers, as well as pregnant women who want added stomach support that is soothing but won't create pressure when they move.