Lifegard Aquatics 300 Watt Adjustable Quartz Glass Aquarium Heater Adjustable from 68-88 ; Length: 15.1" 300 Watts. For aquariums from 110 to 150 gallons (assuming the temp needs be adjusted no more than 10 degree UL Listed Quartz glass tube with bi-metal construction Thermal protection. The heater will automatically shut off if outside of watt