Under tank heater designed to heat the ambient air temperature of your terrarium an average of five to 10 degrees (F) warmer than room temperature. Solid state nichrome heating element with UL/CSA approved power cord. Large for 50 to 60 gallon terrariums uses only 24 watts of electricity and costs only pennies a day to operate. 120 vac, 60 hZ, 24 watts. Instructions Peel adhesive paper off back of heater and "stick" to the underside of your terrarium. Zoo Med recommends you place heater on either the right or left side of terrarium and gently rub heater to make firm contact with the bottom glass. This allows one side of your terrarium to be warmer than the other, thus giving your animals a natural temperature variance. Helpful Hints Use Zoo Med's high-range reptile thermometer to monitor the temperature of your terrarium. Should your terrarium be in a particularly cold area you may need to add an additional Repti Therm UTH heater or Zoo Med's Repticare Rock Heater. Caution Do not use the Repti Therm UTH Heater on plastic or wood terrariums. Provide adequate ventilation below pad to prevent overheating. Product includes eight-page illustrated Instruction Book with complete instructions, cautions, and frequently asked questions.