6.5mm OUTSIDE, Welting/cording foot  for Industrial walking foot Pfaff machine.  Old stock,  used , original German manufactured. see pictures and satisfy yourself to the use on your machine. (Photos are representative) Ask to see actual pictures of item before purchase.  Could have surface rust and/or possible grinder re-modeling.   These are NOT made in China!!!  They were made in Germany and are Vintage. ( they carry the German manufacturing marks as well as the product and size marks)