Charlotte Pipe 6 in. DWV PVC FTG Cleanout Adapter with Plug PVC 00105X 1400 - The Home Depot
Pvc Outer Plug O.d 20-32 Mm Water Supply Pipe Fittings Threaded Water Pipe Plug 4 Points, 6 Points, One Inch Blocking Cap - Pneumatic Parts - AliExpress
NIBCO® 6" MIP PVC Cleanout Plug DWV at Menards®
NDS PVC S&D Cleanout Plug, 6 in. MPT 61P8 - The Home Depot