Its revolutionary, memory foam inner, our pillows cradle your head and neck in a gentle hug for correct alignment of nerves, tendons and muscles whether you sleep on your back, front or side. This high quality inner is long lasting and promises a pillow that will not go flat. Additional Details ------------------------------ Product description: Its revolutionary, memory foam inner, our pillows cradle your head and neck in a gentle hug for correct alignment of nerves, tendons and muscles whether you sleep on your back, front or side. This high quality inner is long lasting and promises a pillow that will not go flat.