There are really only 2 editions of the Catechism. You are probably looking for the 2nd edition (1997).
The green covered one
published by the Libreria Editrice Vaticana/USCCB Publishing is the one I would recommend, even though it's a bit large. In edition to containing the modifications made from the 1st edition, it also still has the Glossary and some great indices, all of which are handy. I don't think any of the pocket-size printings from other publishing companies (with one exception noted below) have the glossary or most of the indices
The full text is available online: scborromeo.org/ccc.htm
. That website also lists the differences between the 1st and 2nd editions
, most of which are relatively minor.
If you want to go all out, you can special order the version from St. Paul's Publishing in Australia
. It's a bit pricey, but it is a pocket-size version that contains the full text, all the indices, and the glossary. It contains everything in the big green version but at a fraction of the size.