Z812Z812 12" FLO-THRU TRENCH SYSTEMZurn Z812 12" [305 mm] wide pre-sloped trench drainage system. Glass-filled polyester fiberglass drain channel with 1/8" [3.18 mm] per foot bottom slope. All sections are modular 10-foot [3.05 M] lengths with interlocking ends. Complete with heavy-duty Dura-coated steel frame w/ anchor studs at surface, combination anchor tabs/leveling devices at appropriate locations and extra heavy-duty ductile iron grate-classC w/ lockdowns.