Koina Wireless Presentation SystemComprised of a transmitter, a receiver, and a charging box. The lecturer uses the transmitter for commentary, while the visitors listen through the receiver (receiving headphones), effectively blocking out external noise interference. The commentary can be transmitted over a long distance.100-800Yards. The channel reception technology allows for multiple teams to mix and visit the same space without interference. The wireless audio guides are not only suitable for museums and science centers but also for team introductions, tourist attractions, factory tours, and many other venues.