Modules: Designed to Make Everything Easier It?s designed to fit virtually any residential or light commercial need. It?s designed for flexibility right at the job site. It?s designed to keep an installer?s inventory to a minimum. What is it? It?s the modular design of the new Hunter Pro-C controller. Beginning with a 3-station base unit, the Pro-C can be expanded with up to three more 3-station modules. Thus, a contractor no longer needs to stock ten different types of controllers (3-, 6-, 9-, 12- and 15-station units in both indoor and outdoor models)?he simply needs to keep on hand just 3 items (indoor and outdoor Pro-C base units, and 3-station modules).