Napco GEM-EZM4 4 Zone EZM Expander for 816/1632 Only Increases the capacity of Napco Gemini control panels by adding up to 16 zones Can be configured four different ways: 4 zones, 8 zones, 12 zones or 16 zones Multiple 4-zone and/or 8-zone modules can be combined Compatible Control Panels: GEM-P816 and GEM-P1632