Front Air inlets for air flow when the trailer has to be closed up. Works well with the MaxxFan, and I can close them simply with screw in caps underneath. I intend to add two more of these to the trailer, as we all know the coolest air is going to be under the trailer on a hot day. They are spaced such that I can fit an air conditioner between them and eventually use the ports to feed the condenser with fresh air while exhaust will be panned and ducted out the bottom and forward.