Ebo Jager 250 watt Heater Ebo-Jager 250 watt approved to UL 1018 aquarium heater (submersible).   • 17.5 inches long with a 10 inch heating element   • For aquariums up to 120 gallons. For larger aquariums use multiple units   • Built-in thermostat accurate to 1/2 degree F.   • Low water level safety switch.   • Two mm thick glass versus standard one mm for extra shock resistance.