ISTA Twin Display Thermostat 500W/300W/100W Heater 50~500 FISH TANK Salt Water Buili-in five electronic EXPLOSION AC100~240V 50/60 Hz universalvoltage 1. State of the art electronic thermostat and split type. 2. More safe and convenient: explosion proof of tubular heater will not happen during the process of water replacement. 3. For the safety, when the heater leaves water surface that heating process will be cut off automatically. 4. Relay is built in, free from EMI. 5. Control temperature range: 20C~35C, deviation: +- 1C. 6. The confirmation with CNS qualified of standard.