Download Non Convex Mesh Collider FREE Unity. 

Compatible with all Unity Versions starting with Version 5.

Super easy to use.

Solves the ‘Non-convex Mesh Collider with non-kinematic Rigid Bodies are no longer supported in Unity 5.0’ problem.

Works with every mesh.

Is blazing fast.

The script can be added to a gameobject at runtime or in the editor.