intulon 6-inch to 5-inch Portable A/C Exhaust Hose Coupler/Adapter/Reducer – Omnidirectional – Clockwise or Counter-clockwise Thread – Intulon
Vent Systems 6" to 5" Inch Duct Reducer Adapter Connector Fitting Pipe Increaser Reducer Cone for HVAC Ventilation Systems, ABS Plastic PVC Pipe 150 to 125 mm - Amazon.com
Plastic 6-Inch to 5-Inch, 4-Inch Converter Cone Reducer for flexible/PVC Pipe | eBay
6" to 5" Duct Reducer Round Reducer Duct Fitting Pipe Increaser Reducer PVC DWV (Drain, Waste and Vent) Reducing Coupling (Plastic, 6 inch to 5 inch) - Amazon.com
Master Flow 6 in. x 4 in. 26 Gauge Reducer 26R6X4 - New - Walmart.com
Vent Systems 6" inch to 5" inch Duct Reducer Adapter Connector Fitting Pipe Increaser Reducer Cone for HVAC Ventilation Systems, ABS Plastic PVC pipe 150 to 125 mm - Amazon.com
6" to 5" Duct Reducer Round Reducer Duct Fitting Pipe Increaser Reducer PVC DWV (Drain, Waste and Vent) Reducing Coupling (Plastic, 6 inch to 5 inch) - Amazon.com
NDS 4-in PVC Sewerand Drain Coupling in the Sewage Pipe & Fittings department at Lowes.com
Zoro Select PVC Reducer Tee, Socket x Socket x Socket, 6 in x 6 in x 4 in Pipe Size 401532 | Zoro
DURA 5 in. x 2 in. Schedule 40 PVC Reducer Bushing SPGxS 437-486 - The Home Depot
Amazon.com: HG POWER 5 Inch Dryer Vent Hose, 16 Feet Long Flexible PVC Hose, Three Layer Noise Reducer Hose Aluminum Ducting for Heating Cooling Ventilation AC Exhaust Black : Appliances