This is the back wrap that uses clinically proven Photobiomodulation Therapy (PBMT) to temporarily alleviate lower back pain. Its medical-grade lasers emit laser light waves at 650nm that penetrate beneath the skin to increase blood flow and temporarily relieve joint pain and muscle aches. Unlike LEDs in similar devices that produce a broad range of scattered light waves, the laser diodes in this belt emit a concentrated beam of light that results in higher intensity and deeper penetration of the epidermis. The belt has a breathable fabric exterior that contours to the shape of your body and secures with hook-and-loop fasteners. Automatic 30-minute shut off. Recharges via battery pack. Comes with carrying case and belt extender. Fits waists up to 61" (with extender).