They claim to be unbreakable. That's right UNBREAKABLE, under normal circumstances even if you get rough with them. There's no Glass, so nothing to crack when they over heat, not that they can overheat anyway. This device is equipped with a safety thermal switch that stops operation if it's out of water.
Modern plastic heater with termoregulation.
Wide range of precise regulation
Fully submersible (IP68 Standard)
Overheating switch control
Easy to install and service