RCB10A Waterproof Conductivity Pen Type Meter. It is economic, but accurate, easy using. RCB10A ... this10 series is replaceble, and large capacity electrode, cost down, life span long. Handy, IP67-waterproof and long-lasting, ... so light, they float! Applications• Water & wastewater treatment • Boiler blow-down • Electroplating rinse tanks • Drinking water • Hydroponics • Printing Industry • Aquaculture ...