Some time ago, this black plastic tool was given to me by a guy from an LBS, and I remember thinking "oh, that might come in handy".

Now, a couple of months later I've completely forgotten its purpose. What is it for?

Unknown black piece of plastic

I know what the coin is for, but not the other thing.

  • 3
    Aside - if you can put a ruler in the photo rather than a coin, it gives a better idea of size. I've never seen a euro coin and have no idea how big it is.
    – Criggie
    Jan 16, 2023 at 19:50
  • 3
    The diameter is exactly 19.75 mm. Or just over 3/4" for our US friends.
    – Berend
    Jan 16, 2023 at 19:58
  • 1
    For comparison, the US small one-cent coin is only slightly smaller (19.05mm).
    – tripleee
    Jan 17, 2023 at 10:00
  • 1
    The 10 euro cent is good for some old style screws if you have nothing better at hand.
    – nightrider
    Jan 17, 2023 at 11:14

1 Answer 1


It is a valve core removal tool for presta valves. They can be used to replace a valve core or to temporarily remove the core when filling sealant through the valve (for tubeless tire setups).

  • Yes of course, now I remember!
    – Berend
    Jan 16, 2023 at 14:00
  • 10
    Pro tip: Put it in a zip baggie with a label before dropping it back into your tool box/drawer.
    – shoover
    Jan 17, 2023 at 0:32
  • 3
    Less common use: remove or install valve extenders.
    – Weiwen Ng
    Jan 17, 2023 at 7:19
  • I’d add that it’s plastic which is likely to fail. There are metal versions (Schwalbe makes a nice one) which are much stronger.
    – Michael
    Jan 17, 2023 at 12:14
  • 3
    For trailside (and home) use I really like the valve caps that have an integrated core removal tool. They are never misplaced.
    – jaknudsen
    Jan 17, 2023 at 20:53

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