Condar Watchman Electronic Catalyst Monitor Powered by 9v Battery (#9-90) Fahrenheit temperature display for catalytic wood-burning stoves & fireplaces Programmed audio signals the proper temperatures to open and close a stove's bypass Indicates declining combustor performance and need for replacement Ideal for stoves made by Vermont Castings, Fireplace Xtrordinaire and other brands Designed & manufactured in Columbus, North Carolina USA