For anyone interested in rider to pillion communication I have got this,,,,,, "Interphone Connect Bluetooth Intercom"

It is a brilliant bit of kit. Really clear sound. Also connects to phone, sat nav, other bikes if you want, waterproof and has built in radio. ect .

Easy to fit into each helmet and so far perfect sound even at 70mph.

I only wanted it so I could talk to my daughter on the back and make sure she was ok, and to be honest that's probably all I use it for (I'm not a teck lad),, but it will do lots more if you wanted it too. Little on the expensive side but worth it.

Can get them on eBay, Amazon, Sports bike shop,,,,,,the usual places.

Anyway if you're in the market for something like this,,,,, check them out

 

Pat

Love my sena.  Never used it for intercom though, just music 

A decent budget option is Freedconn TCOM bluetooth intercoms. Partner and I have used them for years. We ride separately and I can vouch for the fact that the set works over quite some distance as I can hear him swearing when he's stuck at lights and out of sight behind me ;-).  They give a single channel at a time and you need to push a button to change channels to talk to a third person, so they work best as a 2 person solution but ideal for us. My top tip is earplugs - you hear your comms so much clearer with filter plugs like Earpeace or Pinlock.