The NIBCO 4 in. x 4 in. x 3 in. PVC DWV All-Hub Sanitary Tee connects a branch line into a vertical PVC drain line in a non-pressurized sanitary system. There are 2 types of DWV plastic: ABS (black plastic) and PVC (white plastic). The sanitary drainage and vent piping are installed to remove waste water and water-borne wastes from the plumbing fixtures and appliances.