This goes behind the e-ring that locks the rear limit cam in place, it is metal, and the color is steel. We sell over 100 different used parts. Please let us know if you have any questions. Pre-owned, needs deep cleaning, has rust, everything works and is ready to use on your chair. This is for one washer that goes behind the e-ring that locks the rear limit cam in place, and is a genuine OEM part for the Aeron furniture line by Herman Miller.