These Pharaoh rods contain zero epoxy and use rubber ends caps to hold the crushed quartz inside the copper and zinc galvanized steel tube when held balance the ions in the body copper side positive and zinc side negative producing around .75 volts.  Tubes are 1" diameter by 5" long which allow for about 4" of metal contact.  The rubber end caps fit extremely tight, protect the ends of the tubes and do not come off easily.