Quick Questions about genesis power base converter

[Crush Crawfish]

Hello. I have recently heard about an adaptor for the genesis that allows you to play master system games on it.

This sounds like a great item to have, but I just have a few questions:
1. Is it rare and expensive?
2. Does it work on the model 2 genesis or do I need the original?
3. Do all master system games work with it or are some incompatible?

Thanks for any help!

[GameGuru]

Ooops, looks like you double posted. Check your first post for my answer to your question. :)