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Detail of the LOX (back) and fuel high-pressure ducts. These ducts carry high-pressure propellants from the turbopumps to the main propellant valves, on their way to LOX dome and the fuel manifold, respectively.

As an early production engine, the high-pressure ducts are flexible, internally-tied high-pressure ducts. The ducts had flexible bellows to allow for relative movement between the turbopump and main propellant valves. Later production engines had rigid high pressure ducts.

In this photo, one of the flexible bellows is visible on the turbopump (bottom) side of the fuel high-pressure duct. I've noticed the silver bands or caps (which are apparently installed to protect the bellows) on either end of the straight portion of the high-pressure ducts on these early engines, but this is the first photo in which I've actually seen the bellows.