Interpretation ID: aiam2034

Mr. H. Melvin Strand, President, Duo-matic Importers LTD., P.O. Box 1436, Colorado Springs, CO 80901; Mr. H. Melvin Strand
President
Duo-matic Importers LTD.
P.O. Box 1436
Colorado Springs
CO 80901;

Dear Mr. Strand: This responds to Duo-matic's August 19, 1975, question whether Standar No. 121, *Air Brake Systems*, applies to an air brake coupler device that connects air brake hoses from a truck to the trailer it tows.; The answer to your question is no. Paragraph S3 (Applicability) o Standard No. 121 states that the standard applies to trucks, buses, and trailers equipped with air brake systems (with some stated exceptions). The standard therefore applies only to vehicles, and does not apply to motor vehicle equipment such as the Duo-matic coupler device.; Sincerely, Frank Berndt, Acting Chief Counsel