Wall-mounted Speaker Size: 184.85mm×275.38mm×124.56mm 2SIPlines Mainspeaker15W/8O can be connected to external 15W/8Opassivesub-speaker Built-inmicrophone,supportmonitoring,self-test, intercomapplication Support 20 multicast partitions Built in 24M Baudiofilestoragespace,support scheduled task broadcast Customize audio files for emergency notificationand alarm 3short circuit input detection, 1short-circuit output ,linkage security alarm device Support external IP camera video linkage Support Web remote adjustment volume Black