ABS P-trap with a swivel union for the under-sink drain that needs to come apart cleanly for service — loosen the union nut and the trap separates so you can clear a blockage or pull the trap entirely, then re-seat and re-seal without cutting pipe. The U-bend holds a water seal that blocks sewer gas from rising through the fixture. Both ends are hub sockets sized for Schedule 40 IPS ABS, solvent-welded for a rigid joint, while the union keeps the assembly serviceable. It's a LESSO America ABS DWV fitting conforming to ASTM D2661 and CSA B181.1 with NSF/ANSI 14 and cUPC listings — the marks an inspector checks on a residential or light-commercial rough-in across the GTA. Stocked in 1½" for standard sink and lavatory drains. DWV service only; test hydrostatically, never with compressed air or gas.