Question: Thank you for answering our mail, according to your info. this stove is a cat. Regarding cat. stoves we have heard that the cat. has to be replaced in a certain time, so we would like to know what we should do if it is plugged, how much to replace and shipping. We know that this stove, although is 10 years-old, hasn't been used much. We would really appreciate if you could give us more info regarding cat. stoves. Our computer is not set for pictures yet, so we can't e.mail you one. Thank you again, for your time. Answer: There are some articles about cat stoves at https://www.hearth.com/what/specific.html another good source is: http://www.appliedceramics.com/FAQ.html if it is is good condition and has not been used much, it's possible a decent cleaning of the cat is all that's needed. Cat usually degrade physically before they degrade chemically, so if the cat is in good shape that may be a clue that it still works. Many stoves allow for a temperature probe to be inserted neat the cat to monitor temperature. Check out http://www.condar.com for some of these probes...and also for replacement catalytic converters.