Product description Specifications: 50W, 100W, 300W Size: 50W - 20.5cm length, 100W - 26.5cm length, 300W - 30.5cm length Color: Black Material: Glass Package content: 1 pc fish tank heating rod 1. Application Suitable for freshwater and marine aquariums, Betta tanks, frog enclosures, newt habitats, turtle tanks, aquaculture setups, glass containers, and hydroponic systems. 2. 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 set point, the heater automatically resumes heating (LED on). 3. Safety Features Fully submersible design constructed from shatter-resistant quartz glass. Includes automatic safety shut-off to prevent overheating. 4. Easy Installation Ensure the thermometer is fully submerged in water for several minutes. The temperature controller is adjustable from 59F to 95F. Press the set button to adjust to the desired temperature. The heater will begin operation once set. Place the heating rod at the water outlet and fully immerse it in the water. 5. Easy to Use Equipped with a temperature knob for simple adjustment to your desired setting. Made with 2mm thickened quartz glass suitable for both freshwater and saltwater aquariums.