Created to provide relief from back pain by helping keep your spine straight while sleeping. The articulated center bends at the knee to provide maximum comfort and performance. Ideal for knee, spine and nerve problems. Great for pregnancy, athletes, the elderly and others. The larger bottom pad rests between your calves to ensure proper positioning. Straps hold pillow in place. Removable cover is washable. 15" x 6" (38cm x 15cm), top pad: 2" x 6" x 6" (5 x 15 x 15cm), bottom pad: 4" x 6" x 6" (10 x 15 x 15 cm)