This double headed ear clip electrode is designed for use with TENS 7000 and most standard TENS units. The ear clip design fits a 2.0mm rod connector for a secure, easy connection. Built with durable rubber and a reliable clip-on structure, it is reusable for repeated use. Usage note: please keep the surface of the earlobe slightly moist when using this ear clip electrode to improve contact. Clean the clip after use and store it in a dry place.