The fuel injection line nuts on top of the pump are not easily accessible by regular wrenches. American Bosch had a wrench like this one made, it is not currently available. Gary Agrimson used his wire EDM and made quick work of converting an S-K socket into this specialized wrench.
I didn't take a picture of the near pristine S-K 3/4 deep socket. The cut can be seen but since the wire EDM removes almost nothing it almost looks intact.
Here the two halves lay apart, the notch in the end to get over the lines can be seen.
End to end it is longer than necessary.
Wire EDM was used to cut this close fitting joint.
The socket started out 3.25 inches long, the finished wrench is 4.2
The fit is very close and it will be welded on the inside.
The inside edge was chamfered, then TIG welded.
All discoloration from welding heat was shined off on a Scotch-Brite wheel.
This is the special purpose it serves, it needs to be this tall to stand above the lines.