... Up to 180m Certificate: CE, RoHS 2.4G Digital Two Ways Audio Guide Device How to use: One more ... of guests. Guests use the 2.4G Digital Two Ways Audio Guide Device to follow the lecturer and ... listen as they walk. One RC2408TX transmitter can be directly selected, and ... . After the grouping, use the 2.4G Digital Two Ways Audio Guide Device to follow the lecturer and ...