Why would I need this tool for my SL?

[strelnik]

I still haven't gotten the owner's manual, and as I look around for info on the 380SL, I came across a tool kit that includes all the "must have" tools for the 107.045:

Mercedes/Heyco 21mm (13/16") Spark Plug Wrench with Spring Flex head
Mercedes Open end wrench set - 8x10, 11x13, 14x17, 17x19 mm
Mercedes/Heyco 17mm Lug Wrench.
Screwdriver with Double ended Flat bits and Double ended Phillip bits-also used as Tubular wrench driver.
9 piece Mercedes Branded Spare Fuse Kit.

I understand all those but why this one:

Mercedes/Feelisch 10mm double ended tubular wrench.

Is this a part for the fuel injection system? Certainly not for the spark plugs.

Is this guy earnest or is he just advertizing?

Thanks!