Herman Miller Aeron Adjustable Arm Yokes Left Right chair Polished Aluminum Pair. These attach to the swing arm, go up and down with thumbwheel on their chair armchair. We sell over 100 different used parts. Please let us know if you have any questions. Pre-owned, needs deep cleaning, they show wear, metal is ground down, have discolorations and need to be polished or may need touch up paint, but will still work on your chair. Need thumbwheels to adjust. Flip tabs won’t work. This is for one pair of polished aluminum adjustable arm yokes, and are genuine OEM parts for the Aeron furniture line by Herman Miller. 127 W Fairbanks ave, #254 Winter Park, FL 32789.