I’ve had one in place for 2.5 years and go into the fine UT red dust a lot. It works quite well. You still have to obsessively seal your bed too I think, but the vent keeps out a lot of the fine stuff that filters in no matter what. In my experience a Bedrug really helps too. The vent also keeps the camper interior from heating up when on the road. I just leave mine open all the time. Also works well for nighttime venting with the Max fan on low.
Fergie’s comparison is pretty great evidence IMO.
It’s a Lewmar Marine Hatch vent and I found mine on West Marine; you can see some pics there. Jay put it in at my install, but now he’s making it a option. Pretty easy install though if you want to DIY. The filter and clip to hold it is DIY.
Here’s some pics installed
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