6000×2000 ground protection boards for civil Engineering MasterSeal 975 Drain Board (DBS 6200) 4x50 ft. MasterSeal 975 Drain Board (formerly SonoHDPEeld DBS 6200). Polypropylene Drain Board System with Cut Protection Layer and fold out overlap flap. Flows 18 GPM/sqft veal rate. 4 Wide x 50 foot Roll (200 Sq. Ft.).