This is a Left and right 448 mm steel chassis railsReplacement part for these models:TRX-4® 1972 Chevrolet® Blazer® High Trail Edition™TRX-4® 1979 Chevrolet® Blazer®TRX-4® 1979 Ford® Bronco®TRX-4® Equipped with Traxx®TRX-4® Ford® Bronco®TRX-4® Land Rover® Defender®TRX-4® Sport High Trail Edition™TRX..