Product description Specifications: 50W, 100W Size: 50W length 20.5cm, 100W length 26.5cm Colour: Black Material: glass Package content: 1pcs fish tank heating rod 1.ApplicationApplicable for freshwater and marine aquariums, Betta, Frogs, Newts, Turtles, aquaculture, glass containers, and hydroponic systems 2.Intelligent temperature controlAutomatic constant temperature function, when water temperature reaches to specified temperature value, heater will automatically shut off(LED Off), when it is lower than the target temperature, heater will automatically start heating(LED on). 3.Warm tipsThis heater is fully submersible, constructed of shatter-resistant quartz glass and features an automatic safety shut-off to avoid overheating. 4 .EASY INSTALLATIONMake sure thermometer is completely submerged underwater for minutes, temp controller is adjustable from 59 to 95F , just press set button to the set temperature, it begins to work.Please place the heating rod in the water outlet and completely immerse it in the water. 5.Easy to useyou can adjust the temperature knob to set the temperature what you want easily,2mm thickened quartz glass,can be used in fresh water and salt water aquariums