The Original Headrest for The Herman Miller Aeron Chair (HW, Onyx). 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 while using modern technologies. Headrest only; CHAIR NOT INCLUDED. Designed for ergonomic performance. Forward and backward angles can be locked for a custom fit and lasting comfort.