Fountek Neo cd3.0 T/S

T/S specs don't make as much sense for ribbons for these reasons :

Their impedance is flat without a resonance peak (atleast in the band of frequencies where you won't destroy the ribbon)

They are typically fully enclosed accept for ones meant to be used as dipoles (no nead to model boxes)

Frequency responses are readily available from themanufacturer and since its almost purely a resistive load thats pretty much all you need

You'll get all the info that you need here :

http://www.fountek.net/products_neo_30.htm

--Chris