Upgrade Portable Air Conditioner Sliding Door Vent Kit with 4-In-1 Coupler Filter Suitable for 5.1/5.9” Exhaust Hose，Adjustable from 16" to 90" Ac Vent Kit for Window/Sliding Door. Coupler Filter fits 5.1 "/13cm exhaust hoses,prevents debris from entering the AC ventilation hoses to better protect the air conditioning components.