TENS technology (Transcutaneous Electrical Nerve Stimulation) provides safe, temporary drug-free relief from lower back pain. The belt has an integrated TENS unit making it comfortable to wear under clothes whilst also being discreet.The belt is easy to use; simply wet the integrated pads and wrap around your lower back. The belt fastens at the front, making it easy for you to adjust and choose from the 4 programms and 20 intensity straps. As the pads are connected through moisture and held into place with the belt there is no need for future replacements.The buttons can be locked so you can maintain the perfect setting whilst you go about your day. The belt is suitable for waists of 75 - 140cm (29.5" - 55.1").