I can’t find any other thread related to this.
I’ve just ordered a dark-blue FA filter, and due to the lack of space in my case, I wondered if those filters could be used outdoor? I could plug it at the antenna, but it is (of course) not sheltered.
I don’t know the official answer. I’ve had mine hanging out of the bottom of the utility box without issue. No direct rain, but lots of moisture. With enough self-sealing tape, anything can be used outdoors.