Double v-belt Alt/AC...one is loose.

I have 3 sets of belts and tried mix and match many combo's with the alt/ac/crank but still having the noise starting at about 2200rpm. Every once in a while it will go away. I was looking around under the car and noticed what looks like a 1 piece felt ring at the dampener. It is loose and I can spin it freely. Any idea what it is from? I moved it in between pictures. Thanks.
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