Twin Air Part # 177764R1.75"" Diameter Round Vents. The Airbox Vents increase airflow into the airbox, resulting in more clean air around the filter for added performance. The Airbox Vents come 2 per pack with a hard plastic cover to close off the vents that snaps into place for extreme conditions. Installation is simple, use a 1 3/4"" hole saw drill bit to drill the hole in the airbox. The vent then snaps into place.