The ICM-600 expansion module is only compatible with controllers within the Hunter I-Core series. These controllers include the Hunter IC-600-PL, the IC-600-SS, the IC-600-PP, and the IC-600-M. The plastic model can be expanded from 6 to 30 stations and the metal enclosure is expandable from 6 to 42 stations. Each of these controllers can be purchased at Sprinkler Warehouse online and in-store.