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Detail of the fuel return manifold.

Fuel flowed down two adjacent tubes, cooling the engine wall (known as "regenerative cooling"). It reached the fuel return manifold (the silver ring at the exit plane of the thrust chamber), where it returned through two "up" tubes, reaching the fuel manifold and then being injected into the combustion chamber.

Note the marking for No. 120 tube. Even though this is a "fuel-down" tube, the arrow is for some reason pointing up (i.e., toward the throat). This marking is between two tubes; presumably, the tubes on either side of this mark lead back up to the single main No. 120 tube at the bifurcation joint.