The Hartley Chair is a stylish ergonomic task chair, with mesh back and adjustable arms | The synchro mechanism allows the chair to move with you as you change tasks | Bifma tested with Green Guard Gold certification backed by a 10 year warranty | Simple Synchron Mechanism with Tension Control | Adjustable Arms | Tested to ANSI/BIFMA X5.1-2011 | GREENGUARD Gold Certification | 2 levers