Product information range: 6 inches of vertical, 3 inches of horizontal and cushion contour adjustment to match your postural mood throughout the day adjustment friction is calibrated from the factory, allowing up-down, in-out and tilt position to match your posture. The headrest stays in place wherever you put it. Tension on all axes is easily adjustable with the included tools to suit individual preference. Fits 95% population fits all Herman miller Aeron chairs – sizes a, b or c patent pending design one year warranty – details on site installs in under a minute all tools are provided what’s in the box? Atlas headrest for the Herman miller Aeron chair installation tools detailed printed installation instructions additional information videos on installation and adjustment are available online, search “atlas headrest” please send a message to receive details on international shipping options.