I am converting our 2018 GLC300 to conventional tires, so I purchased a MB OEM Vehicle Tool Kit (165-580-69-00).
This came with a number of tools, all of which I have figured out, with the exception of a little plastic tool.
I hope someone will be able to give me a quick answer on WHAT IT IS...!
Thanks!

 

Is a part number molded into the yellow item? Do you have a packing list or receipt from the tool kit packaging?

 

Looks like a crayon that dropped off a short bus.

 

It looks like an air valve tool. The slotted end fits over the air valve to remove or tighten them from/in the valve stem. Hope this helps.

 

Also called the schrader valve in the air valve stem.

 

No packing list and no part number on the plastic tool. There's a "D" on one shoulder (?Dunlop)...
Also, there's no list of the tools included in the kit that I purchased...

 

Thanks for the replies about the valve core tool - I also thought that might be what it is...

The tools for the Schrader valve core insertion/removal that I found listed online are all metal, so I wasn't sure about this plastic tool - or why it would be included in the kit that I purchased...

With any luck, I will not be sitting on the side of the road wondering why I need this little tool...