New Black Herman Miller Aeron Back tilt limiter part. Fits all size chairs -A B or C sizes . There are 3 different versions of this part for aerons so please confirm that this is the correct version! I have many Aeron parts so please let me know if you are looking for parts for your chair. I also have B and C size chairs available for sale on ebay. Email me with questions. We have lots of other aeron parts at aeronsale.com.