Fully submersible cautomatic aquarium heater./Made with extra tough polymer and aluminum / Virtually unbreakable / Designed for safe and continuous use / Resistant to sudden temperature change /Sensitive and reliable thermostat ensures a constant  temperature / Compact and highly efficient heating elements / The clear temperature indicator on the cap enables easy and ??precise temperature adjustment / Supply with strong suction cups and hooks / Outer protection cap featuring a rubber seal / Overheat protection : heater shuts down when out of water and /restarts automatically when in water.