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 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 61°F to 90°F (16°C - 32°C). A good range for most fish is 76° to 80°F (25- 27°C). A few species need to be kept several degrees warmer, and some species require temperatures a few degrees cooler. 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 64°F - 93°F. 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.