The Robertshaw SlimZone® Deluxe (2701-002) zone control panel can be expanded from three to seven zones by adding SlimZone Deluxe expander boards (2701-003). These units are added to the system in two-zone increments. A total of two (2) expander boards can be connected to the SlimZone Deluxe zone panel, allowing for a total of seven zones. The SlimZone Deluxe zone control panel powers the SlimZone Deluxe expander boards.