Engineered Now The Original Headrest For The Herman Miller Aeron Chair H3 Lead. Please be sure to select the correct’Size’. H3 – For individuals under 5’11” (Under 180cm) H4 – For individuals 5’11” or taller (Over 180cm). COLOR AND WEAVING – Lead Carbon – Color Code 3D02 – The Engineered Now Headrest perfectly matches your Aeron Chair in comfort, quality, color of frame and Mesh and the mesh weaving. Please make sure you choose the right Model and color of your chair, see our images and text for assistance. 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. H3 – For individuals under 5’11” (Under 180cm) H4 – For individuals 5’11” or taller (Over 180cm), COLOR AND WEAVING – Lead Carbon – Color Code 3D02 – The Engineered Now Headrest perfectly matches your Aeron Chair in comfort, quality, color of frame and Mesh and the mesh weaving.