An example would be a specific number of units being selected as an indicator for when more units need to be produced. When this number of units is reached in inventory, then more units will be produced. This helps to keep inventory levels lower than they have to be and costs down, right in line with other lean manufacturing techniques.
Needless to say, with companies producing millions of units of materials, having this system in place is extremely important, and having a tool to manage this system is even more important. These tools can be linked right to the regular ERP system or any other system that your company uses, and in doing so the system is able to actively monitor where you are in your production cycle.