About A Chair AAC 253 office chair by Hee Welling

HAY introduces the AAC 253 as "balancing the high functionality and modern expression of the five-legged castor base with the softness of the upholstered shell." It shares the same dimensions and design as the AAC 252, including low armrests, in either standard or quilted upholstery.

The upholstered shell, and what the textiles are

The shell is the same as the un-upholstered models, molded recycled polypropylene, according to the HAY product sheet, but here it is fully covered. Foam is applied over the shell and then finished with the chosen upholstery: the contact is softer, and noise is better dampened in high-traffic rooms. In return, upholstery must be cleaned by blotting rather than spraying.

The upholstery options offered here: Hallingdal 65, a Kvadrat wool blend (70% wool, 30% viscose), the company's classic and very durable fabric; Sense, HAY’s full-grain aniline leather: it reveals the grain and develops a patina over time. The so-called quilted variants—HAY uses the term quilted—feature stitching that compartments the padding: the stuffing does not shift over time, and the texture breaks up the solid surface.

The base: five legs, castors, and gas lift

The base is a five-legged cast aluminum star—HAY writes cast aluminium five-legged castor base—mounted on castors. Five legs instead of four: this is the standard for stability in rolling chairs, as a four-legged chair tips too easily when leaning forward.

A gas lift adjusts the seat height. It is a pneumatic cylinder: a pressurized nitrogen cartridge, operated by the lever under the seat, which lifts the chair effortlessly and locks it at the desired height. It requires no maintenance and can be replaced as a spare part if it eventually loses pressure.

Note on height dimensions. HAY publishes a single overall height for these chairs. Since the seat is adjustable via gas lift, this value corresponds to a specific position, not a fixed height.