AQUATOP Glass Aquarium Heater w/ Protective Guard - 300W Submersible Heater - Up to 60 Gallon TankThe HTG Series is our premier line of fully submersible glass heaters with thermostat control. Our HTG heaters offer a compact design for versatile placement and are extra durable due to the built in glass element. The thermostat control makes it simple and easy to adjust the temperature setting and the sturdy guard helps to protect the glass heater from accidental breakage from large fish or turtles. Aquatop s HTG Series is suitable for both