06-10-2020, 02:14 PM
Thanks, all. Interestingly, upon further inspection, I see what appears to be a maybe 3"x4" patch of fabric near one end. I wonder if that's meant to hold some sort of filter. In normal times I wouldn't even give that a thought, but nowadays I don't know. Although if it were meant to hold a type of filter, I would expect it to be open at the top to slip the filter in. This is open at both sides. I tried to take a picture, but between poor lighting and my lack of a third hand, it was futile.