I have a Squire 50500 in my fireplace. Got it for $75.00 from a burned down house. "no the insert didnt cause the fire". I installed it in my own fireplace about 10 years ago. I have a perfectly good 10" square chimney. I put an 8" flu liner straight up through it. Welded all the seams and attached it directly to the collar on the top of the insert. I seen a post from someone back in june of 2008. I read through the whole thing and noticed someone had mentioned an aftermarket catalytic retro fit burner. Is there one of these available? I'm getting tired of cleaning my flu 4 times a year. I use this insert 24/7 durring the winter. Any input would be greatly appreciated.