Support AUX audio and microphone input at the same time; connect your external devices with AUX cable(not included); such as tablet; smartphone; MP3; PA system; you can add background music when speaking. Simple operation; turn off all receivers with one key; without complicated operations; suitable for large-scale occasions such as tour guides and conference translations. PLL synthesis design; worked great with almost no interference; no interruption or decrease in sound quality; no more yelling for people to hear. 49 channels optional; allows 49 groups to operate simultaneously at the same location within range; use the audio system in noisy environment without worrying about being affected by other teams. Longer transmission distance; working range up to 100m/328ft in open area; receivers do not have to be clustered around the transmitter; useful information can be heard clearly; Note: It can only be used with Retekess T130S Receivers.