Begins locking pain immediately and provides relief even after you turn it off. Easy to use no wires, no assembly, no doctor needed. Wire-free device can be used on the go. Feel it begin working at the touch of a button, strength/intensity is adjustable (63 levels). What is Tens therapy? Ten stands for Transcutaneous Electrical Nerve Stimulation, a method that was once only available to doctors and physical therapists. Smart relief Tens Therapy is applied right to the point of pain to safely and effectively send gently waves of relaxing pulses to the underlying nerves that are affected by pain. Therapy System includes: Control unit reusable (with preloaded battery) Electrode reusable (refill pads sold separately) Replacement Battery 3V CR2032. Powerful, portable pain relief. Relieves even chronic pain. For tough or persistent pain, it's often difficult to find relief. Now you can get the same Tens technology used by your doctor, for a fraction of the cost and without a prescription! For persistent sore or aching muscles, for relief of chronic pain associated with arthritis. Begins locking pain immediately and provides relief even after you turn it off.