Uniclife 200W Submersible Aquarium Heater with Thermometer and Suction Cup, 50 Gallon FULLY SUBMERSIBLE: Water-tight sealing IP68 waterproof design, Strong suction cup clamps TIGHTLY FIX the heater to the tank vertically. Measures 11.5" x 1.2" (L x D) EASY ADJUSTMENT: Maintains at temperatures that range from 61F to 90F (16C - 32C). A good range for most fish is 76 to 80F (25- 27C). A few species need to be kept several degrees warmer, and some species require temperatures a few degrees cooler. EXPLOSION PROOF: 2 mm extra thick Quartz Glass is shatterproof and prevents electricity leakage. Due to made of glass, it may be damaged during shipment carelessly. Please Contact us for a free replacement or refund immediately. Comes with 1 year replacement for EXPLOSION PROOF WARRANTY SIMPLE PRACTICAL THERMOMETER --Designed to be simple to read and easy to attach (just peel and stick), the paper thin 5.2 by 0.7. Using color indication, the water temperature that the thermometer reads will change from white to a blue color. The measurement range is 64F - 93F. HT-2200 heater is suitable for 26 to 52 gallons aquariums or aquariums up to 35 inch in length, suitable for most tropical freshwater and marine aquariums. An aquarium heater is very important for your fish tank set up if you have tropical fish. By rotating the Knob at the top of the heater you can simply control the temperature from 61 - 90 F. Once you set the temperature, it will turn on and off automatically to maintain the temperature. The heater must be fully immersed and should be placed diagonally vertically in the aquarium, rather than horizontally. You can easily install it by attaching the suckers to the glass. By using this Thermometer, you will be able to monitor and maintain a suitable temperature that directly affects fish&#039;s health. An easy to identify blue color shows the current temperature of your aquarium water.