Please make sure you select the correct size. H3 – For people under 180 cm – H4 – For people 1.70 m or more (over 180 cm) COLOR AND WEAVING - The Engineered Now headrest perfectly matches your Aeron chair in terms of comfort, quality, frame color and mesh and mesh weave. Please make sure you choose the correct model and color of your chair, see our pictures and text for help. Discover the ultimate upgrade of your Herman Miller Aeron - The H4 ENgage is our full size headrest designed to provide you with the neck support that Aeron chairs lack. The H4 comfortably fits users over 5'6", offers more adjustment and a 20% larger pillow size. Chair not included. CARBON COLOR - Perfectly matches your classic Aeron chair in terms of comfort, quality and colour, with a complementary carbon mesh. [Fits classic Aeron chair models from 2016 or earlier] IMPROVES POSTURE & PRODUCTIVITY - Our headrests are ergonomically designed to support the head and neck, helping you stay comfortable, aligned and focused throughout the day. Adjust to your comfort: EN headrests are meant to be smooth. Tilt and vertical adjustments move freely, while the front and back adjustments can be locked for your best comfort. 100% GUARANTEED TO INCREASE YOUR COMFORT OR MONEY BACK - Fully covered by Amazon's A-Z Guarantee. This headrest comes with a 2 year manufacturer's warranty.