From Honda Trail Bike Wiki
There are many different intercom manufacturers, offering products with similar functionality. Prices vary massively, and these are write-ups on those tested.
[edit] Multi-purpose intercoms
These devices usually run off the bike's power and are extendible to permit combinations of rider-pillion, rider-phone, bike-bike, GPS-rider, MP3-rider etc.
Starcom 1
Autocom Avi Pro
[edit] Rider pillion intercom
Oxford Bike Mike
[edit] Bluetooth helmets
BMW System V
Nolan N-com
Caberg Just Speak
[edit] Blutooth headsets
Suitable for connecting to one Bluetooth device, such as a mobile phone or GPS. Some GPS devices can play music and daisy-chain to a mobile phone.
[edit] Scala Rider
Full details to follow.
The Scala Rider available from DirecetMobileAccessories.
[edit] Motorola HS830
To follow.