Fits perfectly, bought another one to be ready next time. A few years ago I was fed up with being ripped off every time my boiler was serviced "professionally". I learned it myself and I guarantee you that no "professional" I've ever hired has replaced my fireproof! All they ever did was stick a shop vacuum in the combustion chamber. as our new president would say, "You're fired!" Don't be a chump, I encourage you to master this skill and with this kit you can do it once and do it right. A+