Reduce your gap, reduce your fuel cost! The Aero-Max Trailer Gap Reducer fits into the gap between your cab and trailer, reducing your drag and improving your semi truck’s aerodynamics. The cab-trailer gap is the greatest inhibitor to aerodynamics, as wind becomes trapped in this space sucking the vehicle backwards. To compensate for this extra resistance your vehicle’s engine must work harder, consuming more fuel. With custom color options available, built-in front and top running lights, and an easy-to-install mounting system, the Aero-Max Trailer can make any semi or tractor trailer into an aerodynamic trailer!