For night-long comfort and a restful night's sleep, the Back on Track Mattress Overlay is a must. Using our state-of-the-art Welltex material, our Mattress Overlay works with your body's energy to create a soothing far infrared effect. This effect may help to improve blood flow, reduce inflammation, and help with general body aches or back problems. Many happy customers have woken up feeling less stiff. The Mattress Overlay is ideal for use in both summer and winter, under your fitted bedsheet.