The Biorb Intelligent Heater has a built in sensor that automatically adjusts the temperature 3000 times per minute to keep a constant temperature in your aquarium. It is made from polycarbonate which makes it much more durable than traditional glass heaters. Since it is a small disc it takes up less space inside your tank and you can place it at the bottom instead of suctioning it to the side of the aquarium. Reef One's Description - It couldn’t be easier to use. Simply plug-in and drop-in. The heater is permanently set to 24.5°C. A built-in sensor checks and adjusts the water temperature 3000 times a minute and is accurate to 0.5°C. Accuracy means it’s more economical. The Intelligent Heater uses less electricity than a traditional aquarium heater. Typically, it costs just pence per day to run. It’s a tough little thing. Traditional aquarium heaters are made from glass. The Intelligent Heater is made from polycarbonate which is much stronger. This means you can safely place the heater within your décor without fear of damaging it. Small, but mighty. The Intelligent Heater is suitable for all of the biOrb range and similar sized home aquariums.