The internal machine that drives the device, made of metal, also some plastic parts and the color of the knob is a graphite-black.

We sell over 100 different used parts. If you want to figure out what is wrong with your chair, and how to fix it, buy our twenty minute diagnosis via email, text, video or call for $20.00, purchase at this link, https://rcannon8156.mystorefront.online/?l=1&product=10059&action=product

If you are in Florida we might be able to come to your location and repair your chair for you, if you are interested please ask us for a quote, so we can let you know how much it will cost.

Please let us know if you have any questions.

This is pre-owned, needs a Rear Tilt Cam, also needs a deep cleaning, it shows wear, there are gouges, nicks, scratches, scuffs, rust, the knob may need touch up paint, but it is ready to be put to work on your chair. Has the new era sector gear, see the schematic.

This is for one tilt engine that fits the small size A chair, the metal hex shaped bars are about 10 inches apart so they won't fit the size B or C chairs, and it is a genuine OEM part for the Aeron office furniture line by Herman Miller.

If you want multiple parts we can combine shipping.