The Balance MTR Magnetic Back Brace provides powerful natural pain relief for the lower back helping back strains back spasms and sore aching muscles. Back spasms are primarily caused when muscles do not get enough oxygen. And after a back strain pain is caused by swelling and damage to muscle tissue. Regulating blood circulation is crucial to getting effective back pain relief for these conditions. The Advanced Biomagnetics used in the Balance MTR back brace are specifically designed to improve blood flow in the lumbar back. By affecting ion channels these strong magnetic fields help the body relax and constrict capillaries depending on what response is needed. Constricting capillaries decreases blood flow. This reduces swelling tenderness and pain caused by back strain or injury. Relaxing capillaries increases blood flow. This brings more oxygen to muscles to relieve back spasm and help regain flexibility. It also carries more nutrients to cells to help speed up healing after an injury or strain. Strong 4 300 gauss ceramic magnets for back pain relief. Increases blood flow to relieve back strain swelling and spasm. Breathable neoprene provides all-day comfort. Velcro adjustable fit and compression. Pumps out heat and sweat. Pulls in cooler drier air. Provides all-day comfort. Great for sports and exercise. Supports joints and muscles. Weather-proof for outdoor use. Soft skin comfort. Size: Large. Waist (inches): 33 - 42.