No microphones on any of the pairs. They do all have two black rings, but isn't this standard?

I don't want to buy new headphones, as the pair I had been intending to use are a rather nice sennheiser pair. Given that one of the main uses I had planned for my nexus was in flight entertainment this means it isn't fit for purpose.

Edit:
I've seen adapters (for iphones) which apparently have the same problem. These have three rings on them, but look to be longer.  I guess these will just not interfere with the sloping case.

Will grab one (couple of quid on eBay) and report back.