This boat cover support vent/pole combo by ShoreMaster Fabric Products supports your boat cover while allowing air to circulate freely, reducing condensation, mildew and rust. Consists of a strong two-piece vent and an adjustable aluminum support pole to secure the proper height for drainage run-off. Installation is fast and easy. Vent stays permanently attached to the boat cover and can be used with or without the support pole. Support pole telescopes from 32" up to 58".