The Beurer EM38 Lower Back Support Belt & TENS Device provides targeted and comfortable muscle pain relief around your lumbar lordosis. It utilizes electrostimulation targeting the lower back. The ergonomic belt fastens at the waist and it includes an extension strap and batteries. The flexible belt fits a waist circumference of 30-55 inches (with the extension). This unit features an LCD display panel (a removable control unit) which indicates if the unit is turned on, visualizes the timer, and allows you to choose the intensity and program. You can easily increase or decrease the intensity with the buttons on the device. The EM38 has 4 channels and 20 adjustable intensity levels for you to choose from. The belt has 4 water contact electrodes, which eliminate the need (and additional costs) of replacement electrodes and contact gel, and it is completely reusable. What is TENS? TENS (Transcutaneous Electrical Nerve Stimulation) treats the area directly by working in harmony with your body to alleviate both severe and chronic pain. The low voltage electrical current travels through the electrodes and into the skin stimulating specific nerve pathways to produce a tingling or massaging sensation that reduces and suppresses pain signals.