This bolts onto the swing arm yokes, fit the small size A chair, made of plastic and mesh, the color is gray. We sell over 100 different used parts. Please let us know if you have any questions. This is pre-owned, needs deep cleaning, shows wear that may need touch up paint, but is ready to be put to work on your chair. This is for one back frame with the mesh that goes on the swing arm yokes. This fits the small size A chairs and is a genuine OEM pieces for the Aeron office furniture line by Herman Miller. 127 W Fairbanks ave, #254 Winter Park, FL 32789.