This is a heavyweight commercial plugin for Acrobat – if you think 195 US dollars is a lot of money, you are not their target market. There is a free trial version to try so you can see what it offers.
When run you get a new menu option under Advanced called PDFCanOpener allowing you to access the functions. One of my favourite features of PDF CanOpener is that you can also edit and manipulate objects.
The website says that PDF CanOpener needs Acrobat 6 or 7 but it seems to work okay with 8 and 9. I suspect the reason for not listing 8 and 9 may be that Acrobat added similar functionality in Acrobat. This may well have reduced the commercial market for PDF CanOpener as Acrobat 8/9 provides lots of drill down capabilities included in (and on non-Windows platforms as well). Acrobat does not have all the functionality of PDF Canopener for editing and modifying objects.
So if you work with Windows and need a heayweight tool to drill down into a PDF file and see what it going on, PDF Canopener is well worth a spin, especially if you are on an older version of Adobe Acrobat. Do you have any particular favourite features on it?