Thanks ThinkTubes; yep those are Sachs-Huret "ARIS" group indexed 6 or 7 speed. They work very, very well. Not lightweight by any estimate, but they shift with the authority of a 12 gauge shotgun going into battery. Also they have never required post-install adjustment. The indexing is so widely spaced with a 7 speed freewheel that there's a lot of room for wear/stretch if set up correctly (the Barnett's method of derailleur adjustment).