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ACX Pad

Antonio Citterio, 2026

Thanks to its self-regulating synchronised mechanism, the ACX task chair provides optimum comfort for users of different sizes – without them having to adjust anything except the seat height. Despite these advanced technical functions, the chair has clean lines and an inviting, uncomplicated appearance. The construction, materials, production, logistics and maintenance of ACX are all designed to achieve a long life cycle – with the smallest possible carbon footprint.

The ACX Pad has an upholstered backrest with a patent-pending lumbar support that automatically adapts to different users. Available in a wide range of fabrics and colours, the cover can be removed and refitted at any time, making it easier to clean or replace.

Self-adjusting lower back support

Thanks to its ingenious design, the patent-pending lumbar support developed by Vitra instantly adapts to the shape of the sitter's back and provides support in the lumbar region.

Information

User Manual
Colours and materials
CAD data
Product and safety information
Dimensions
Product family

ACX

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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.

This product was designed by

Antonio Citterio

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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.