Perform-O-Flex features an inner liner of synthetic rubber. A partial coverage protective sheath of stainless steel braid is embedded in the liner during manufacturing. The reinforced hose liner is then bonded to a full-coverage outer protective sheath of high tensile stainless steel wire braid. Tougher than this, hose doesn't get. Yet Perform-O-Flex, with its inner liner, remains flexible at temperatures between -40 and +300 degrees F. Racing greats have depended on Perform-O-Flex hose and Swivel Seal hose ends since 1972.