About A Chair AAC 25 office chair by Hee Welling

HAY writes that "the softness and warmth of the upholstered shell temper the executive weight of the AAC 25." It features the same four-star swivel base on castors and the same dimensions as the AAC 24, available with standard or quilted upholstery.

The upholstered shell, and what the textiles are

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

The covers offered here: Hallingdal 65, a Kvadrat wool fabric (70% wool, 30% viscose), the company's classic, highly durable; Coda, a Kvadrat wool fabric (90% wool, 10% nylon); Sense, HAY's aniline leather, dyed through: it shows the natural grain and develops a patina with use; Divina, a 100% wool Kvadrat fabric with bold color; Remix 3, a heathered Kvadrat wool fabric (92% wool, 8% nylon).

Castors, but no gas lift: the distinction to know

The base is a four-star aluminum star base mounted on castors, upon which the shell swivels. This is what HAY calls a four-star castor base.

This model does not have a gas lift. The seat height is fixed. This is what sets it apart from the About A Chair 50, 52, and 252, whose five-star bases feature a pneumatic gas lift. We mention this because it is not visible in photos, and because it is the primary criterion for a workstation: to adjust height at a desk, you need a gas lift; to roll from one point to another around a table, castors are sufficient.

Three base finishes: polished aluminum, black powder-coated, or white powder-coated.