ACX Softknit High
Antonio Citterio, 2026
Thanks to its self-regulating synchronised mechanism, the ACX office swivel chair provides ergonomic comfort for users of different sizes. Only the seat height requires manual adjustment. The aesthetics, construction, materials, production, logistics and maintenance of ACX are designed with a focus on longevity – while keeping the carbon footprint as low as possible.
The backrest of ACX Softknit High is covered with a three-dimensional form-fitted knit textile whose structure provides a pleasant cushioning effect. A self-adjusting neck support supports the sitter's head and neck when leaning back and helps to maintain a level field of vision. This alleviates tension in neck muscles, even during extended periods of reclined sitting. The neck support can also be manually tilted and its height adjusted if need be. The fabric cover of ACX Softknit High is produced out of post-consumer recyclate obtained from plastic bottles in a zero-waste process and can be removed and refitted.
Self-adjusting lower back support
Information
ACX
ACX is the tenth office swivel chair that Vitra has developed in collaboration with Antonio Citterio. With its self-regulating synchronised mechanism, the compact ACX offers maximum comfort for every user – while exhibiting a distinctly non-technical appearance. The construction, materials, production, logistics and maintenance of ACX are designed to achieve a long life cycle with the smallest possible carbon footprint. The ACX mechanism and lumbar support instantly adapt to a wide range of user weights: even lightweight and heavier individuals can sit down and enjoy immediate comfort and optimum support throughout the full scope of movement, without having to adjust anything except the seat height. That makes ACX particularly suitable for environments in which dynamic collaboration processes have replaced sitting for long periods in the same chair. The design of ACX features a limited number of components, which simplifies service and maintenance. The covers of all models can be easily removed and replaced. All parts are made of recycled materials whenever possible – as much as 60% for certain models – and can be easily separated and recycled again at the end of the product's life. This also applies to the new V-Foam used in the seat cushion, which is the world's first recyclable polyurethane foam. As a result, ACX is up to 100% recyclable, depending on the chosen configuration. ACX has a casual and relaxed appearance: with its clean lines and choice of knitted fabrics in a variety of colours, it functions as a design element in the office – instead of a necessary addition tolerated for the sake of ergonomics. ACX is the ideal chair in any setting that calls for healthy ergonomic seating combined with an understated inviting aesthetic, a focus on longevity and compliance with rigorous environmental standards. The product family includes a number of different versions: ACX Light, ACX Mesh, ACX Soft, ACX Pad, ACX Pad High, ACX Softknit and ACX Softknit High.
Antonio Citterio
The architect and designer Antonio Citterio, who lives and works in Milan, has collaborated with Vitra since 1988. Together they have produced a series of office chairs and various office systems, as well as products for the Vitra Home Collection. The Citterio Collection is constantly being expanded.