Two way communicator/intercom for trailer...

[Drago]

Trust me, he'll be wanting some that actually work!

 

[mick1836]

Try http://www.precisiontandems.com/tandemcomwireless2.4questions.htm

http://www.ehow.co.uk/info_8348903_handsfree-communications-bicyclists.html

http://www.ehow.co.uk/info_8348903_handsfree-communications-bicyclists.html

 

[Piemaster]

@nurglespuss I've got a pairof freequency pmr201 I'm not using if you're interested.
Not been used for a long time but were bought when my son first started cycling on local roads with me so I could tell him how to deal with junctions etc.