Hunter Pro-C PC-400i 4 Zone Base Controller; Indoor with Plug-in Transformer Comes with 4 zones, accepts optional modules to expand up to 16 zones Non-volatile memory: keeps programs indefinitely without battery backup One touch manual start and advance: allows user to start or test any station Rain sensor bypass: allows the controller to ignore sensor devices when needed Solar Sync dial position: now available with built-in Solar Sync programming for increased installation efficiency