This is a genuine BMW ball joint, part number 07 11 9 987 011. The number stamped on the part is 07119987011; BMW's catalog files it under the short number 9987011. You will find it on our Supplies & Hardware shelf, under Group 11.
It fits the E36 convertible (318i, 323i, 325i, 328i and M3, 1994–1999), with the M42, M43, M44, M50, M52 or S50 and other engines — and the European-market versions.
BMW draws it on the Single Parts F Vibration Absorber (61_0096) diagram. It weighs about 4 g (under 0.1 lb).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.