Product Specifications: 50W, 100W, 300W Size: 50W – 20.5cm length, 100W – 26.5cm length, 300W – 30.5cm length Color: Black Material: Glass Package Content: 1 x Fish Tank Heating Rod Application: Suitable for freshwater and marine aquariums, Betta fish, frogs, newts, turtles, aquaculture, glass containers, and hydroponic systems. Intelligent Temperature Control: Features automatic constant temperature function. When the water temperature reaches the set value, the heater automatically turns off (LED off). When the temperature drops below the target, the heater automatically resumes heating (LED on). Warm Tips: This heater is fully submersible, made of shatter-resistant quartz glass, and includes automatic safety shut-off to prevent overheating. Easy Installation: Ensure the thermometer is fully submerged in water. The temperature controller is adjustable from 59°F to 95°F. Press the set button to adjust to the desired temperature; the heater will begin operation accordingly. Place the heating rod at the water outlet and fully immerse it in the water. Easy to Use: Adjustable temperature knob allows easy setting of desired temperature. Constructed with 2mm thickened quartz glass, suitable for both freshwater and saltwater aquariums.