GSS = German Stainless Steel

I don't remember the exact model, but it was used in one of the face inserts.  I have a Circle T Newport 303 GSS that I play with and the GSS just has a softer feel than regular SSS (IMHO).

Indeed GSS stands for German Stainless Steel.  It has a unique chemical makeup that creates softer feel compared to American...or another stainless steel.  It's very expensive and there are several putters on tour made entirely of GSS.

Scotty launched the Studio Style line several years ago that featured a GSS insert in an effort to mass produce this "tour-only" type feel. 

From a performance perspective, it's just another tool in the Cameron inventory used to fine tune high performance putters.

RC

I didn't really like the Studio Style, but I do love the TeI3 inserts.  I've never rolled a GSS Scotty, but it's a pretty looking putter.