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Heat Wrap covers a wide area of your carboy or fermentation vessel, promoting an even heat distribution. Using tape to adhere, it can be attached directly to your fermenter. You can increase the temperature of your ferment from 5-20 degrees Fahrenheit. To decrease the temperature differential, stick only a portion of the FermWrap to the fermenter. 32 watts of heat spread over almost two square feet, it provides gentle even heating.