Simultaneous interpretation may also use portable equipment or “bidule”. The only difference with traditional simultaneous interpretation equipment is that in this case there is no booth. This system is very similar to tour guide systems. With this interpretation system, the audio of a speaker is streamed to a simultaneous interpreter, who wears headphones with a microphone. He or she interprets the speech in real time, and the interpretation is streamed to auditors, who also wear headphones connected to wireless receivers. Portable equipment systems are generally used for meetings with few participants or when participants have to change venue during the event. This option is suitable for a wide range of events, among others factory visits, training courses, and small meetings.