The EHEIM Jager TruTemp Fully Submersible Aquarium Heater, rated at 250W, offers a range of features to ensure optimal water temperature control in marine and freshwater aquariums. Its thermo safety control feature prevents running dry incidents by automatically shutting off when the heater is out of water, and the shatterproof glass construction ensures durability. With precise temperature regulation and a TruTemp dial featuring a re-adjustment ring, users can calibrate the heater for precise temperature readings tailored to their aquarium's needs. The heater is fully submersible and waterproof, with an extra-long 5'6" cable for flexible installation. It includes a clamp with two suction cups for secure mounting and is suitable for aquariums up to 159 US gallons. Additionally, an on/off indicator light provides convenient operation.