YukiHalu Small Submersible Aquarium Heater, Adjustable Mini Fish Tank Heater 25W 50W 100W 200W 300W with External Temperature Controller, LED Display, Used for 5/10/20/40/60 Gallons (50 Watts)

Automatic constant temperature with 1℉ accuracy.

The heater works in variable frequency mode based on PID control strategy.

Out of water protection / Overheating protection.

Never cook your fish E1: out of water protection.

The power will be cut off and stop heating automatically if the heater leaves the water or the heater do not fully immerse in the water.

Display 'E1' error code.

The heater will re-work if it goes back to water.

H1: Overheating protection.

The power will be cut off and stop heating automatically if the water temperature exceeds 93°F.