Designed to fit under your back in four positions: lumbosacral, lumbar, thoracolumbar, and thoracic, to bring relief to specific problem areas. Exclusive patented dual air cell pouch allows for independent angled joint separation. The two angled air cells vector apart to lift and stretch the lower back in a unique way, decompressing and aligning your joints. As the dual air cells lift and expand your spine, nutrient-rich fluid lubricates the joints, and promotes disc expansion and disc hydration. The bottom of the lumbar unit is rounded to allow you to do an abdominal stretch/pelvic tilt, thus increasing the stretch of the lower back. If your back is sensitive or extremely stiff, first use the unit on your bed/mattress. As your flexibility increases, you may wish to graduate to a firm, flat surface. While most lumbar units have only one air cell, the Posture Pump® Disc Hydrator® Elliptical Back Rocker™ Model 2000 is a patented dual air cell device, allowing you to achieve a unique lengthening and stretch in your lower back.