this unit i have is new,but used,it was bought years ago an never used,appartently no one that i have spoke with has no idea of even what it is ,any experiance here in nl so far is the type that comes in the stove.is the only model any has seen,when i entered on goggle the info i have on my catalytic box,this is the site i was directed to,and still am researching the net as to find out more info on my unit,i was kinda thinkin in the direction that the catalytic comb, needs to be very near to the direct heat in orderf to use it,so my thinkin was if i installed this farther up the flue,that means the pipe would have to withstand the same heat as the box,so i wasnt fussy on havin a 18 inch flue before the box turnin red in order to use the catalytic box,so in turn with the one connector i have comin out of my stove i will place the box on,,,,,,,,, it should receive good heat that close in order to operate the catalytic box....,,,,,