8' galvanized trolley rail, designed for doors weighing up to 450 lb, can be used with many types of single & multiple brackets, galvanized coated steel, use with 24" Golfcrest True Value Hardware #770956, Golfcrest True Value Hardware #773125, bracket spacing, screws for attaching rail are packed with brackets (order separately), meets ansi/bhma a156.14, grade 1 specifications.