yes
no
no

The thing is just a small heater.

It raises the internal temperature a bit, thus lowering the relative humidity in the enclosure.

I'm going on 20 years on mine... it still works and seems to do a fine job. No issues.

Don't expect it to do much in a real humid environment... it's for a safe in a reasonably dry location.

"The price of good shotgunnery is constant practice" - Fred Kimble