Finnex TH-S 500W Titanium Heater Tube

THH Titanium Heating Tube Virtually unbreakable titanium built heating element Out of water sensor protection + audio alert Corrosion resistant titanium High temp resistant heater guard   The THH heater series are designed to be used with an external controller.  Warning:  THH heaters cannot be operated without a temp control unit.  Do NOT plug the heater into a wall outlet!   THH heaters have an internal sensor that detects when the heater tube is exposed to the air.  If the water level drops too low and exposes the heater, power to the heater is turned off.  This prevents over-heating of the aquarium, saving your prized aquarium life from harm.  The heater cord has a signal box with LED status liights.  Green means the heater is functioning as normal.  A red light indicates the low water switch has been tripped.  The heater is constructed of corrosion-resistant titanium, making it safe for freshwater and marine aquariums.  The titanium tube is virtually unbreakable and featu