It's probably not the exact one you're looking for, but the ARP Fridge Defend works well:
https://www.arprv.com/products.php#4-arp-3.1-2-fan
Wiring setup is a lot more involved than the basic PC fan, but it doesn't require getting on the roof and it'll also prevent damage if the fridge is run off-level. I got the version with one exterior fan and two interior fans for my
Bigfoot. The exterior fan made it work well in hot weather instead of falling behind above 94F ambient, and the interior fans keep the temperature a lot more uniform.