The PRO-EX3 Wi-Fi-enabled controller is an indoor/outdoor irrigation controller that utilizes a hybrid modular and two-wire decoder system, designed to provide maximum installation flexibility. The unit consists of a master valve/pump start, test, common, sensor terminals and one pre-installed 4-station module. With the addition of separately sold 4-station and 8-station modules, the total modular station capacity can be expanded to a maximum of 24 stations. This capacity can be further increased to 40 stations through the installation of a 2-wire module supporting up to 36 stations, used in conjunction with the pre-installed 4-station module. The PRO-EX3 is also Wi-Fi-enabled when paired with the optional 3100-BRIDGE Wi-Fi module.