The EHEIM Jager TruTemp Fully Submersible Aquarium Heater, rated at 300W, offers precise temperature control for both marine and freshwater aquariums. It features a thermo safety control system that prevents running dry incidents by automatically shutting off when the heater is out of water. Constructed with shatterproof glass, it ensures durability and safety. The TruTemp dial with a re-adjustment ring allows users to calibrate the heater for precise temperature readings tailored to their aquarium's needs. Additionally, 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 264 US gallons. An on/off indicator light provides convenient operation.