Herman Miller 2 Lever Aeron Mesh Office Swivel Chairs. Ergonomic Size B  Which is the most popular size and average Size in  Black over 20 Available .
These Chairs are considered to be one of the best chairs on the market.
The Herman Miller chairs are in a good condition minor marks only. Odd minor paint chips to frame Read up on chairs and see the outstanding reviews 
They are Height Adjustable. And have  Seat Tilt  Adjustable  the arms are Fixed.. they are big arm rests for maximum comfort And with Tension  control. All of these Chairs have New Back Adjustable Lumber Pads. Also they have been fitted with a new front of seat pad that goes just under the mesh for back of leg comfort 
The chairs are built for maximum comfort. Built in lumber support on the back plus have an added brand new lumber back support pad . Mesh back and seat. Brilliant chairs at a good price