300 Watt In-line aquarium heater suitable for all canister filters with 5/8 in. flexible hosing. No danger of damage if unit is run dry for short period as the ETH will switch itself off before overheating. Heats with high efficiency and designed to avoid temperature variations caused by poor water circulation. UL listed. Reliable and simple to use. Extremely accurate. Suitable for freshwater and saltwater aquariums. Ideal for tropical fish breeding situations. For aquariums 53-80 gallons. 300 Watts - 12 inch