Two posts before james michael's opportunistic response I wrote;
"Just had two calls from interested parties who agree with FTDK in that it is passive. Both however agree the msot likely place to have a mid air would be in class E airspace or where TCAS equiped aircarft operate so the unit enhances MK 1 eyeball".
I unfortunately mis-interpreted the advertising. I did not post this to cause trouble, simply to pass on an advertisement that I thought would be of benefit to those concerned with mid air collisions.
If an apology be needed to succour the hurt of james michael, please take this as personal an apology that I can humbly offer in the circumstances.
I am advised MRX is $850 and XRX is $2500 Australian.