Office chair, Herman Miller - Mirra 2 Butterfly Graphite.
Ergonomic office chairs Herman Miller with a 12-year warranty.
Chair Mirra 2 with mesh back (Butterfly).

Chair description:
Synchronous mechanism with negative angle inclination - YES;
Fully adjustable armrests - YES;
Adjustable lumbar support - YES;
Wheels for hard flooring - YES;
Graphite frame color and back - YES;
Back fabric color Black - YES;
Seat fabric color Graphite - YES;
Armrest color Black - YES;
Adjustable seat front - YES.

Video on how to adjust the MIRRA 2 chair.

Lean, light and as responsive as your own shadow
 
Support for people who work in a constant state of motion
As work evolves, and we become more active, shifting from individual to collaborative work in an instant, we need tools designed to be as agile as our work style. To address this need, the designers at Studio 7.5 set out to create a high-performance chair that supports people who work in a constant state of motion.
Immediate comfort and personalised ergonomics
Mirra 2 moves with the person, at one with the body. When you sit, the seat and back adapt instantly. With dynamic surfaces that respond to your slightest movements and simple, intuitive adjustments to fine-tune the fit, Mirra 2 balances immediate comfort and personalised ergonomics in a single sophisticated design.
Support in motion
Support for seated movement starts with a flexible yet supportive design that allows your body to move freely and naturally. Mirra 2’s Loop Spine provides torsional flex, allowing you to stretch and reach laterally, while the Harmonic 2 tilt provides a smooth, balanced feel as you recline.
Butterfly back or TriFlex
Two back options help Mirra 2 work for a variety of people and applications. The ultra-responsive Butterfly back results from inventing a method for merging a fabric layer with polymer veins to create a dynamic hybrid structure that acts like a suspension membrane. The TriFlex back meets more rigorous cleaning protocols because there is no fabric layer.
PostureFit
Both Mirra 2 back options offer passive PostureFit sacral support to keep your spine properly aligned as you sit. And both are ventilated to keep you cool, as well as supported, no matter how active you are.