WOOW DEPOT Aquarium Heater accompanies by a cover guard that fish won't be burned. The main body of the heater is made of Quartz Glass, which is high-temperature resistance, anti-corrosion. Temperature is adjustable with high accuracy that it can be flexible to meet varied submersible environment demands.Product Specification:Type: Aquarium / Submersible HeaterMaterial: Quartz Glass & Nickel Chromium Heating WireColor: BlackIP Rate: IPX8Adjust Temperature：20-34℃/68-93℉Power Available: 25w 50w 100w 200w 300w optionalRecommended Tank Capacity:25W: Within 7 gallons50W: 10 to 16 gallons100W: 20 to 33 gallons200W: 40 to 66 gallons300W: 60 to 100 gallonsProduct Length:25W: 7.8"50W：7.8"100W：10"200W：11.8"300W：11.8"Package Include:1 x Submersible Heater and 1 x Protect CoverNote:1.This heater must be fully submerged in water, otherwise, it will be burnt out or explode.2.Do not insert it into the sand to process.3.When cleaning the or changing the water, be sure to turn off the power 10 minutes in advance.4. Due to different using environment, please allow ±2℃ temperature difference.