What is this?

[dzalphakilo]

Anyone other than two others here know what this is (and you know who you are!)

Hint: It can make you have no air conditioning via your central air.

 

[Spiffy1]

An incredibly dirty air filter?

 

[thcri]

I have seen that B4

 

[dzalphakilo]

An incredibly dirty air filter?

Yep.

Ironically enough, MANY years ago, I made that EXACT type of air filter (same manufacturer) in Auburn, Pa. and can tell you "step by step" how it was made.