Carboy heater from Adventures in Homebrewing.
About from AIH.. “The Carboy Heater is a small heating wrap that is stuck directly to the fermenter to increase heat by 5-20° F. This heat wrap distributes 32 watts of heat over an area of 2 square feet for a very gentle heat. Use electrical tape (recommended) to adhere to your carboy, plastic fermenter, or even your conical! For ultimate control of your fermentation temperature, use in conjunction with a stopper thermowell and digital thermostat.”
As of this posting, AIH has this marked down to just $19.99. Price, promotions and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this this post was published; however, they may differ from those you see when you visit the product page. Check the product page for current price, description and availability
Also: Check out AIH Sale Items – Selection Changes Regularly
More: Recent AIH Finds