It's an adapter. What more is there to say? It'll be fine for any mic with a mini-jack.

As to sub £200 shotgun mics - This one has a really nice spec (but I don't own one, so I can't say for sure how good it is) Beyerdynamic MCE 86 II.2 Condenser Shotgun Microph at DV247.COM - Needs Phantom Power. I've always liked Bayer Dynamic stuff for audio

And then there are the Rode mics - This one for instance: Rode NTG-2 Lightweight Condenser Shotgun Microphon at DV247.COM