Abstract: A fluid conduit system is disclosed which comprises a rigid duct pipe having a cylindrical outer surface, a flexible metal hose telescoped onto the pipe, a clamp assembly securing the hose to the pipe and a seal between the hose throat and the pipe. The flexible metal hose is constructed from interlocking helical convolutions defining a helicoidal interior throat formed in part by a helical recess, has an end region contacting the duct pipe surface and a plurality of generally axially extending slots formed in the hose end region. The clamp assembly is disposed about the hose end region for urging the hose into engagement with the pipe. The seal is disposed in the throat recess for blocking passage of fluid between the hose and the pipe through the recess.