Additional Port Activation enables upgrade in 4-port increments from 8 to 12 and 12 to 16 ports. The base SAN16B-2 Express model activates the first eight ports (0 to 7). You may optionally purchase port activation for ports eight to eleven (first four-port increment), and ports twelve to fifteen (second four-port increment)Includes four 4 Gbps shortwave SFP transceivers.