This is a close up picture of the custom fabricated stainless steel transition piece at the base of the stainless steel stack.  This is transitioning from a six inch pipe within the building to the seven inch stack to be constructed and installed atop this transition piece.   For an earlier picture of this project http://www.dmstorrschimney.com/our-soot-stories/commercial-stainless-steel-stack-construction-in-somerville