12', 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" #769-331, #351-015, Bracket Spacing, Screws For Attaching Rail Are Packed With Brackets (Order Separately), Meets ANSI/BHMA A156.14 Grade 1 Specifications.