Jones Stephens B04401k Features: Covered under Jones Stephens's 1 year limited Constructed of plastic Reduces backflow in drainage system Sockets are Schedule 40 DWV Kit includes: 16" sleeve, heavy duty plastic lid, and adapter 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)