Sockets are Schedule 40 DWV
Reduces backflow in drainage system
Threaded access cover for easy inspection
Magnetic strip for underground detection
Flapper and cover have elastomeric gasket to ensure watertight seal
Stepped construction encourages flow (minimum 1/4" per foot fall)
The 1-1/2", 2" and 6" have UPC, SBCCI and CSA approvals
The 3" and 4" are NSF approved and UPC approved!