Finally, an authentic replacement
In reading many negative reviews of supposed HQ8/52 replacement heads from many different suppliers, I finally chose one.  I received two factory-sealed sets of triple heads in a Philips Norelco box, on which was printed: "made in Netherlands".  The manufacturer's barcode was covered with what appeared to be the supplier's barcode sticker (see photo).  The heads fit snuggly and were identical to my original 7310XL shaver heads, down to the finest physical detail.
Rating: 5 stars