You will only need one chatterbox for you and your passenger. However you will have to buy another helmet headset and cord for their helmet. The chatterbox has two headset hookups. Your passenger will hear everything that you do and you have the ability to put the Chatterbox into an intercom mode where the conversation will only occur between you and your passenger instead of being transmitted across the radio. One last note, make sure you get the GMRS version.qkfire said:ok im looking at getting rider-rider communication systems for me and my friends. i want something that i am able to talk to with my rider so she can listen to music throught my head set and then be able to communicate with the otehr riders. the way i understand the chatterbox x1 is that i only need 1 head set for the bike, if she wants to talk to me that is. is that true? and if it is, can i transmit music through her head set or would i need to have 2 chatterbox units to do this?