Yeah it looks like the little 12v can coolers you can get. I suspect it uses a peltier cooler (since it can heat and cool) which can be hit and miss on longevity. They should handle the on/off cycles of the thermostat well though. The one guy claims success with it so I will see how it goes this weekend.
I am leaning away from styrofoam incubators and this one caught my eye. I've also been reading through a cooler-bator thread that has me intrigued. https://www.backyardchickens.com/t/...bator-how-we-did-it-and-test-run-ready-set-go
I have all fall/winter to figure it out since I don't plan to hatch until next spring
Edit: do you think adding another fan inside to circulate the air could solve the temp differences?
From what the one person commented, it doesn't get sufficient air flow with fresh air. I would think that is an issue. Maybe with reptiles it is different but even though you want to hold good humidity, you also want proper air flow in the unit, otherwise I think it would be like a giant petri dish. And opening a unit several times a day? Like Ralphie said PITA!!! just manually turning eggs twice a day can screw things up if you miss once or twice, and constantly having to watch the humidity.