This specification covers hoses (coupled or uncoupled), for use with gasoline, oil or diesel fuel in automotive fuel systems. This hose is less permeable than GM6272M, GM6401M, and GM6196M. Type A hose is intended for high stress applications. Constructions 1, 2, 3, 5, 6, and 7 are suitable for applications subjected to maximum temperatures of 125 degrees or less. Construction 4 is suitable for applications subjected to maximum temperatures of 100 degrees C or less. The hoses described in this specification give varying rates of fuel permeation and also vary in stiffness and flexibility. In general, lower fuel-pemeating hose constructions result in stiffer and less flexible hoses. GM Design Release Engineers who need to specify and quantitate hose stiffness for their specific hose applications can reference the following hose performance tests on their part number blue-prints: GMN4908 (Fuel Fill Hose Sealing Test), GMN4911 (Fuel Fill Hose Pull-off Test), GMN4912 (Fuel Fill Hose Push-on Test), and GMN4913 (Fuel Fill Hose Stiffness Test.