I have a pair of Cardo G4 comm units for sale.
I had one installed in a Shoei Neotec helmet using boom mike and in-helmet speakers. The other was installed in a Shoei full face helmet using a button mic and the option to use either in-helmet speakers or ear buds.
They are both in good working condition.
We've been on many all day rides with these units and were always happy with how they performed.
$125 OBO