An All-in-one Audio Solution Bose Professional's AudioPack Pro S4 is tailor-made for background music and paging. This loudspeaker pack offers all of Bose's legendary audio quality and durability alongside effortless operation, no matter who's using the system. Your purchase includes four FreeSpace FS2SE surface-mount loudspeakers paired with a single FreeSpace IZA 190-HZ integrated zone amplifier.