5" x 4" PVC Schedule 80 Eccentric Reducing Coupling (S x S) - The Drainage Products Store
5" x 4" Flexible PVC Coupling DS56-54 - Buy Online
Canplas 193024 PVC DWV Reducing Coupling, 3 x 2-Inch, White - Pipe Fittings - Amazon.com
4" x 2" DWV PVC Reducer Fitting D102-420
Amazon.com: NDS, 4 Inch, White DWV/SCH40 X S&D Hub PVC Adapter, 4 : Industrial & Scientific
5 x 4" PVC Duct Reducer Coupling 1034-RC-0504
NIBCO 4 in. x 3 in. PVC DWV Hub x Hub Reducing Coupling C4801HD43 - The Home Depot
NDS 4-in PVC Sewer and Drain Adapter in the Sewage Pipe & Fittings department at Lowes.com
The Plumber's Choice 5 in. x 4 in. PVC Flexible Reducing Coupling with Stainless Steel Clamps E73845X4 - The Home Depot
5" x 4" Sch 40 PVC Reducer Coupling Soc 429-490F
Charlotte Pipe 2 in. x 4 in. PVC DWV Hub x Hub Increaser/Reducer Coupling PVC001021200HD - The Home Depot
Vent Systems 4" to 5" Inch Duct Reducer Adapter Connector Fitting Pipe Increaser Reducer Cone for HVAC Ventilation Systems, ABS Plastic PVC Pipe 125 to 100 mm - Amazon.com
5 to 4 inch Reducing Coupling - Duct Reducer Round Reducer Duct Fitting Pipe Increaser Reducer - Amazon.com
NDS PVC S&D Increaser/Reducer Coupling, 3 in. Hub X 4 in. Hub 4P07 - The Home Depot