This is the seal used to keep oil and debris from entering the Valvetronic sensor on 2007+ N51 and N52 engines. The original seal should be replaced often as it allows too much oil into the sensor.
This is a Genuine BMW Valvetronic seal with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.
BMW Fitments:
1 Series
E82 / E88 (08-13) > 128i
3 Series
E90 / E91 / E92 / E93 (06-13) > 328i
E90 / E91 / E92 / E93 (06-13) > 328xi
5 Series
E60 / E61 (04-10) > 528i
E60 / E61 (04-10) > 528xi
X3 Series
E83 X3 (2004-2010) > X3 3.0si N52 (2007-2010)
X5 Series
E70 X5 (07-13) > X5 3.0si (07-10)
Z Series
E85 / E86 Z4 (03-08) > Z4 3.0i N52
E85 / E86 Z4 (03-08) > Z4 3.0si N52
Z Series
E89 Z4 (2009-2016) > Z4 sDrive30i