Only real difference I have found in vent covers is the color. The white will brighten the inside of the camper when vent is open. The smoke colored helps hold the glare down. But in the end the main reason is to keep rain out and either style does that.
I like running my fridge on LP all the time. Just makes it so I have less to remember. I'd hate to loose frozen food because I forgot to change over when leaving home or going from one site to another. "Keep It Simple Stoopid" is what my wife says.
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