It's impossible to say what object is exactly 2 mm without more context! 2 mm is a very small measurement. Here are some examples of things that could be around 2 mm:

* The thickness of a human hair

* The diameter of a pinhead

* The width of a grain of rice

* The size of a small ant

* The thickness of a piece of paper

Do you have any more information about the object you're looking for? For example:

* What is the object made of?

* What is its purpose?

* Where did you find it?

With more context, I might be able to give you a more specific answer!