How can I save a gameobject's mesh?

Hello, I'm trying to save a copy of my gameobject's mesh using the script below:

 SkinnedMeshRenderer MyMesh = (SkinnedMeshRenderer)gameObject.GetComponent("SkinnedMeshRenderer");
 Mesh winning = MyMesh.sharedMesh;
 AssetDatabase.CreateAsset(winning, "Assets/MyMesh.Mesh");

Although this might save the mesh correctly, I can't do anything with it because ".Mesh" is the wrong file format. I'm looking for whatever format that is the same as the picture below:

Thanks