Charlotte Pipe 6 in. PVC DWV Socket Coupling PVC00100600HD - The Home Depot
Thrifco 6 Inch x 6 Inch Slip x Slip PVC Coupling SCH 40 - 8113778 | eBay
Charlotte Pipe 6-in PVC DWV Hub Coupling Fitting for Sanitary Drain, Waste, and Vent Applications in the PVC DWV Pipe & Fittings department at Lowes.com
6" x 4" PVC DWV Increaser Reducer Coupling (Hub x Hub)/Wholesale Pricing
Harco 6" PVC IPS Knock-on Repair Coupling (G x G) - The Drainage Products Store