What is a shank code?

I purchased some self clinching nuts from PEM and one of the descriptions has a shank code 2, what is a shank code?

Gina C2011-07-31T19:25:14Z

Favorite Answer

It is a specification identifier that describes your nuts. Here is the bulletin describing their specs, and the specs of other codes:
http://www.pemnet.com/fastening_products/pdf/fdata.pdf