M8x16 Low Profile Socket Head bolts - black oxide finish. Grade 8.8. Made in Italy (OAV=Agratti). Low profile socket head bolts are DIN7984. Standard socket head bolts (see comp photo) are DIN912. I believe these were used as brake rotor retainer screws for some of the Porsche big brake kits we used to sell. They should NOT be used with standard BMW brake rotors as these use a M8x12 screw (34111123072). (6a)
BMW parts catalogs (and German auto manufacturers in general) use the term "Fillister Head" to describe what we call an "Allen Head" or "Socket Head Cap Screw" because of a translation quirk rooted in international engineering standards. BMW classifies the fastener strictly by its geometric head shape, not the tool used to drive it.
The Head Shape vs. The Drive Type - In formal mechanical engineering (especially the German DIN and international ISO standards that BMW uses), a fastener is named by combining its outer head shape with its inner drive style:
- Head Shape: A Fillister head (or Zylinderkopf in German) is defined purely by its outer physical shape: a deep, cylindrical profile with straight sides and a slightly rounded or flat top.
- Drive Style: The internal socket—whether it's an Allen (internal hex), Torx, or a traditional flat slot
