Ph electrodes with epoxy body can be used with all Oakton pH meters with a BNC connector (except pH wand and pH/Con 10). choose a single junction electrode for field, clean water, and general purpose applications. Choose a double junction electrode for most applications, including dirty water, heavy metals and organics applications. All electrodes have a BNC connector, and are 12 mm diameter with a 3 ft cable. Each electrode includes a free electrode Saver bottle to extend electrode life