Genova 193204 700 Series P-Trap, 4 Inch, WhiteUsed to prevent the passage of sewer gas from the plumbing system into the house through the plumbing fixture drain. Highlights: Size : 4 inch Material : PVC Series : 700 Special Features : SCH 40 Standards : NSF Certified Usage : For Drain, Waste and Vent Applications? Used to prevent passage of sewer gas from the plumbing system into house through the plumbing fixture drain