Engineered Now The Original Headrest For The Herman Miller Aeron Chair Hw Onyx. IMPROVE YOUR POSTURE AND YOUR PRODUCTIVITY WITH SUPERIOR ERGONOMICS – One size fits all: The new HW fits all heights. Engineered Now Headrest – Wide (HW) for the Aeron is ergonomically designed to support professionals in constant motion. The ideal head and neck support will maximize performance whi. Headrest only; CHAIR NOT INCLUDED. ERGONOMIC DESIGN – Provides head and neck support to help maintain comfort and alignment during long sitting sessions. Designed for ergonomic performance. Free-Floating System – Tilt and height adjustments move freely. Forward and backward angles can be locked for a custom fit and lasting comfort. The ideal head and neck support will maximize performance while using modern technologies.