Unity offers a second batching mechanism through Static Batching. The purpose of this feature is to grant us a way to batch nonidentical meshes of any size into a single batch with a similar goal and methodology to Dynamic Batching, but solving the problem for a different set of conditions. The essential difference between the two batching methods is that Static Batching occurs during application initialization, whereas Dynamic Batching takes place at runtime. We therefore have a lot more control over when and where Static Batching takes place.
Static Batching is available in all editions of Unity 5, but only in the Pro Edition of Unity 4. Unity 4 Free users will need to upgrade to the Pro Edition to make use of this feature. ...