This is a rubber fuel hose elbow at the diesel injection pump using 1 x 13mm hose clamp at one end and 1 x 15mm clamp at the other end.
This hose replaces hose 647 078 04 81, which has been discontinued. This is the lower elbow hose at the injection pump.
The inside diameter of both ends of the hose are the same.
Fuel Hose B is similar in appearance however, both ends have a different size inside and outside diameter.