The 200 W Glass Combined Heater is a durable and powerful heat controlled and water resistant light. The heating function is simply controlled by an on/off control lamp The heater can be fully immersed in water, It is protected against running dry and is suitable for both fresh or marine water. The heat is controlled to a constant temperature. The temperature can be precisely adjusted from 18° up to 34°C and then readjusted if required. The control accuracy is +/- 0.5°C. The glass jacket enlarges the heating surface and ensures an optimum and even heat transfer from the light. This product is made from high quality break resistant quartz glass.