It is a desktop application that only supports Windows at the moment that automates Blender's rendering tasks.  You create a rendering list, where when a render is finished the next one in the queue is started right away, without having to perform any manual task after creating all the necessary renders.  You can also add some additional tasks, such as being notified whenever a render is completed using the Windows native alert system, creating an audible alert after all renders are finished, or shutting down, restarting and putting the computer to sleep after finishing all renderings.  Batch creator is very useful for rendering multiple projects and saving rendering time.  Batch creator is very useful to render several projects and save rendering time, mainly to render several scenes and an excellent tool for small studios that want to have a solution similar to a render farm but with low cost.