Thank you for the photo of your RV's P-trap.
We offer one RV plumbing P-trap, Valterra RV Sewer P-Trap # D50-2215 that you referenced in your question, which is detailed in the linked photo. This part uses 1-1/2-inch fittings and installs using ABS Solvent cement # A05-0303.
For a larger size to replace yours you will probably want to check out a full-service plumbing supply store after measuring yours to confirm its size. view full answer...