The X-Core series is available in 2, 4, 6, and 8 station fixed models. This means that these controllers are not modular and cannot be expanded with the addition of any expansion modules. If these stations are not preferred for your project, Sprinkler Warehouse recommends the Pro-C expandable controller, the PC-400 or PC-400i. These controllers include a base module of 4 stations and can be expanded with the additional purchase of the PCM-300 and PCM-900 expansion modules.