Master Flow 6 in. Straight Oval-to-Round Boot OTRB6 - The Home Depot
IMPERIAL 6.25-in x 4-in Plastic Oval Duct Elbow in the Duct Transitions & Connectors department at Lowes.com
DuraVent 4GWARO Aluminum 4" Inner Diameter - Type B Oval Gas Vent - Double Wall - Round-to-Oval Adapter - VentingPipe.com
American Metal Products Oval Gas Vent 6.9-in x 4.5-in x 7.1-in Galvanized Steel Oval Stackhead Duct Boot in the Duct Transitions & Connectors department at Lowes.com
4 in. Oval To Round Adapter Air Tight ATOSB44 - The Home Depot
Panasonic Ventilation FV-VS43R Panasonic WhisperValue Metal 4-Inch Oval to 3-Inch Round Duct Adapter
Amazon.com: DUNDAS JAFINE ROUND TO OVAL DUCT CONNECTOR : Appliances
Duct Adapter Everbilt Round to Oval High Impact Polystyrene Easy Attachment B2 for sale online | eBay
OARA - Oval-to-Round Adapter
4 In. Round To Oval Dryer Duct Adapter - Walmart.com
IMPERIAL 6-in Galvanized Steel 90 Degree Round To Oval Duct Boot in the Duct Transitions & Connectors department at Lowes.com
Everbilt R2OZW 4 in. Round to Oval Dryer Duct Adapter