Cascade presents the 75W LED Aquarium Heater by Penn-Plax. This heater easily maintains healthy water temperature within a 1? accuracy and can be set anywhere between 68 ? and 89 ? by using the red control knob. Our Cascade Aquarium Heaters are factory set to 76 ? and are safe for either freshwater or saltwater fish tanks. The 75W model works great for 10 ? 15 gallon tanks. Shop Penn-Plax for all Your Pet?s Needs: Penn-Plax is a manufacturer and distributor of top quality pet supplies who specialize in creating excellent pet products for animals both great and small.