It can be difficult to know when your stove is burning at its optimum temperature and whilst it won't harm your woodburner to burn at low temperatures, this will coat your chimney flue in soot which can cause a chimney fire or corrosion.
This thermometer will stick to your stove pipe using the magnet on the back. Just pop it on to the stove and watch the needle move when the fire heats up. When the needle points to 'Too Hot' close the air feed and stop adding fuel until the temperature drops to safe levels again.
For use on vitreous enamelled pipe on stoves burning seasoned wood/ logs, coal and oil.