Not yet had to replace the catalytic wafer in my Buck 91. They use Applied Ceramics for theirs. Is your broken? Stopped up? If the latter, have you tried cleaning it? I've been using mine now for 10 winters and it's still working. (fingers crossed.)

I've been using Condar cats, but for some reason they just don't seem to last. They always look good. They're clean and there are no signs of crumbling. They just don't get up to temperature like the should.