Aqua One Glass Heater 25W is a glass water heater is safe and suitable to be used for both salt and freshwater aquariums . They have an adjustable temperature range between 20-34 degrees Celsius. Aqua One Glass Heater is 24.5cm in length and heats up tanks up to 100Litres. It has a waterproof double insulation and includes suction cups and clips with a power indicator lamp.