"NEW DESIGN!!! No end caps. Quartz is permanently sealed inside copper and zinc galvanized steel tube 4" long by 1" diameter. These rods produce the same direct current voltage around .75 volts when held. Crushed natural quartz stone and fine grain clear quartz is tightly packed in each rod and permanently sealed with epoxy will never come out and make these every durable designed to last!" Cylinders of the Pharaoh Copper/Zinc Filled w/ Quartz 4"x1"-Harmonizers