HOW TALL ARE YOU? Our headrests are offered in two sizes to accommodate a wide variety of users. If you are under 5′-11 (180 cm), choose the H3 model. If you are 5′-11 or taller, choose the H4 model. WHICH AERON DO YOU HAVE? Our headrests are designed to fit both Classic and Remastered Aeron chairs. Note the appearance of the Tilt/Lift Mechanism to determine which one you have. WHAT COLOR IS YOUR AERON? Locate the white sticker underneath your chair. The color code is the last 4-5 digits on the first row. It’s time to get the most out of your Aeron. Engineered Now is proud to offer the fine-tuned H3 and H4 Headrest to enhance your Herman Miller Aeron, elevate your comfort and improve your productivity. From large corporations to home offices, these ergonomic add-ons are a must for every avid Aeron chair owner. Eliminate upper-back, shoulder, and neck pain by adding this headrest to your chair today! EXPERIENCE THE ULTIMATE UPGRADE TO YOUR HERMAN MILLER AERON – The H3 ENjoy is our standard size headrest designed to provide you with the neck support the Aeron Chairs are missing. The H3 continues to be our most popular model, comfortably fitting all users under 5’11. CARBON COLOR – Perfectly matches your Classic Herman Miller Aeron Chair’s with complementary Carbon Mesh. Patented design fits All Classic Herman Miller Aeron Chair models and configurations. [MATCHES CLASSIC AERON CHAIR MODELS YEAR 2016 OR NEWER]. IMPROVE YOUR POSTURE AND YOUR PRODUCTIVITY – Our headrests are ergonomically designed to offer you the support you need to straighten up and be able to remain comfortable, aligned and focused throughout the day – minimizing back and neck pain while increasing productivity. FULLY ADJUSTABLE – Three different adjustment options allow you to fully customize your experience. The headrest “Locks” into position for catered support, but can still be adjusted easily by hand from sitting. With ergonomics in the forefront of our design, the headrest adjustments are intended to be free flowing and to flex with your bodies position in order to preserve an ideal body posture.