I really like the O2-COOL fans from AMAZON-WALMART... This one has a 10-inch blades and runs from 12VDC-120VAC with xfmr and also has internal D Cells Batteries...
Does not take up much space... I have two of them one for each tent bed end...

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My trailer came with two of those bunk fans but both of them only lasted one season. Sure didn't last very long

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Roy Ken