Make your aquarium even better with Top Fin's Submersible Aquarium Heater. This heater provides accurate temperature control that will help keep your aquatic companions happy and healthy in their habitats. Only at PetSmart. Features: Provides accurate temperature control with automatic shut-off Completely submersible Made from shatter resistant quartz glass Double-layer design for even heat distribution Includes: (1) Aquarium Heater Intended For: Aquariums Caution: To avoid injury, follow the safety instructions in the enclosed instruction guide. Unplug heater when not submerged in water. Caution: To avoid injury, follow the safety instructions in the enclosed instruction guide. Unplug heater when submerged in water. Available Sizes: 50 Watt: 5-10 gallon aquariums 100 Watt: 10-20 gallon aquariums 150 Watt: 20-30-gallon aquariums 200 Watt: 30-45 gallon aquariums 300 Watt: 45-65 gallon aquariums Size: 300W.