How do I properly save a procedurally created mesh?

I've procedurally created a mesh in script that renders as expected in the editor. However, I want to be able to save it as an asset for reuse. I have attempted to do so like this: AssetDatabase.CreateAsset(myMesh, "myPath/myProceduralMesh");

This creates the mesh (no extension) in the Project but I can't drag it into the mesh property of the MeshFilter component.

Is there a file extension that I need to save my file with for this to work? What is the correct method?