The JBL ProTemp External is a powerful external flow-through aquarium heater that provides reliable and precise temperature control outside the tank. Installing it in the return hose of an external filter or circulation pump keeps the aquarium free of internal heating elements. This creates more space in the tank, improves its appearance and reduces the number of visible technical components. The external heater is suitable for aquariums ranging from 10 to 600 litres and allows for continuously adjustable water temperatures from 20 to 35C. The modern digital LED display clearly shows the current and target temperatures and enables straightforward operation. Precise control ensures even heating of the water, while the high-quality ceramic heating element operates efficiently and reliably. Thanks to the included adapters, the JBL ProTemp External is compatible with standard hose sizes of 12/16 mm, 16/22 mm and 19/25 mm. Safety screw caps ensure the hoses are securely held in place. For