I installed front and rear Maxx Fan 6200 smoke - same as the 5100. These have been a worthwhile upgrade. $125 is a really great price.
I like that these can be left open to allow the trailer to breath during the hot summer days when it is storage. Also I like the feature that a temperature can be set before bed and with the 10 speed fan the fan will continually go slower until it finally stops.
Steve, Christy, Anna and Phoebe (Border Collie)
1994 Classic 30'11" Excella - rear twin
2009 Dodge 2500, 6 Speed Auto, CTD, Quad Cab, Short Bed
Hensley Arrow hitch with adjustable stinger
WBCCI # 3072