... player 12'' USB SD MP3 Wireless Portable PA Speaker System AK12-203Portable PA System Features:1. USB/SD/MMC/MMS ... . 6.3mm wired mic jack System specifications : Wireless PA System Speaker4 Ohm 12 Inch Woofer Frequency Band VHF 174-270MHzOutput ... *Room, outside(especially suitable dancing, gymnastics, demonstration's loud-speaker, recorded, play) *Teaching, Conference, classroom, military training, ...