A 1-way system is the most common tour guide system and allows for the presenter to talk to their guests. The presenter uses a transmitter device which has a tie-clip or headband microphone connected to talk. The guests listen using a receiver device which has an earphone or headphones connected. These high-quality devices have a range of up to 100 metres and can be used for up to 20 hours. They run on internal rechargeable lithium-ion batteries. The system can support multiple groups across up to 18 channels.