mansfield - crumbling insulation?

So, I scored what I think was a great deal on a Hearthstone mansfield on craigslist. woohoo!

Everything looked good but by the time it made it to our house, the insulation (??) inside on the top was crumbling to pieces.

What is that piece called? I can't seem to find it in internet searches and am at a loss.
Anyone know roughly how much it costs to replace??

TIA

Congrats on the stove!
Ceramic fire baffle #3120-202
Ceramic blanket #3120-201

that's a cheap and easy fix. my heritage has a baffle which is worn. i don't know if that damages the stove, but the secondary combustion won't work right without that consolidating the flame at the top i don't think. plus, you wouldn't want your flame to head straight up the pipe. it has a purpose of some sort. my was under $100 for the heritage.

The mansfield has both a hard fiber board on top of the metal tubes and then on top of that is a fluffy blanket of fibrous insulation that may be what you're concerned about.

The heritage has the hard board only and I've repaired it several times with furnace cement. The damage was from me hitting it with things. I see no reason that the baffle would "wear" out unless you physically damage it. If the baffle has holes in it or has fallen into pieces then it must be replaced, pretty cheap. Let that be a lesson to you to be nicer to your baffle!

Thanks so much for the help! You helped a bunch!