Pantsu_BearAs I understand it, JoWo is one of the big producers of German nibs (Bock, being the other) that then get rebranded by other companies. They produce the nibs for TWSBI, Goulet Pen Company (their branded #6 nibs), Edison Pens and I believe many, many others. The general consensus seems to be that they are high quality.
You can find reference to them in these articles:
http://edisonpen.com/ipgnibs2http://www.richardspens.com/?page=ref/ttp/ipg.htm
You can find reference to them in these articles: http://edisonpen.com/ipgnibs2 http://www.richardspens.com/?page=ref/ttp/ipg.htm