Tetra Submersible Aquarium Heater & Electronic Thermostat. This submersible heater comes with an electric thermostat that is specifically designed to keep 40 to 55-gallon aquariums at a constant 78 degrees Fahrenheit. The indicator lights turn red or green to let you know when it's heating (red) or when it's on standby (green). This heater can be installed vertically or horizontally inside your aquarium.
Helps keep your aquarium at a constant temperature for your scaly sidekicks.
No need to adjust the temperature the built-in thermostat helps keep the water temperature at 78° F, which is ideal for most tropical fish.
Install it vertically or horizontally to help conceal it behind plants or other decor.
Comes with indicator lights to let you know when it's heating (red) or on standby (green).