An office chair, or desk chair, is a type of chair that is designed for use at a desk in an office. It is usually a swivel chair, with a set of wheels for mobility and adjustable height. Modern office chairs typically use a single, distinctive load-bearing leg (often called a gas lift), which is positioned underneath the chair seat. Near the floor, this leg spreads out into several smaller feet, which are often wheeled and called casters. Office chairs were developed around the mid-19th century as more workers spent their shifts sitting at a desk, leading to the adoption of several features not found on other chairs.
There are multiple kinds of office chairs designed to suit different needs. The most basic is the task chair, which typically does not offer lumbar support or a headrest. These chairs generally cannot be sat in for more than a couple of hours at a time without becoming uncomfortable, though they often offer more room to move than higher-end chairs.
The Aeron by Herman Miller.
Mid-back chairs offer fuller back support, and with the right ergonomic design, can be sat in for four hours at a time or longer. High-end chairs in this category, such as the Herman Miller Aeron and the Steelcase Leap are comfortable for long periods. Some mid-back chairs in particular offer customization options that can allow for a headrest to be added. Executive or full-back chairs offer full back and head support. Many executive chairs are designed to be sat in for eight or more hours at a time. These are typically the most expensive office chairs.