Specifications: Voltage:AC 220V/110VBuilt-in Rechargeable Battery: 12V 1.2AHOutput Power:20W(maximun)T.H.D.:<5%Speaker:6"Input Signal:Wire/wireless Mic, Audio(USB)Frequency Range:175MHz-276MHz(Wireless Mic)Sensitivity:10dBS/N:>60dBOscillating:QuartzWireless Effective Range:35M Application: Teaching, assembly, Conference, Church, Parade, Lecture, Auction, Sale promotion, tour guide, assembly,speech,etc.