... h) 3) FM function 4) Play Music connect other Equipment Portable USB mini speaker, outdoor speaker factory outlet The main functions1.Play ... antenna, more powerful! The main technical parametersSpeaker interface:DC-5V/USB,LINE INBattery / power supply:Built-in, 3.7V(780mAh) ... 1%Speaker Impedance:4ΩMaximum SPL:28Appearance Material:Aluminum alloy Portable USB mini speaker, outdoor speaker factory outlet