About A Chair AAC 20 swivel chair by Hee Welling

HAY describes the AAC 20 as having "a more formal expression than its wooden-legged counterparts," with "a distinctive curved shell that offers a soft, unified silhouette" balanced "on legs that fan out from a centered base." The same shell and dimensions as the AAC 22, on a swivel base rather than four wooden legs.

The shell: recycled polypropylene, what HAY calls "2.0"

The seat and backrest form a single injection-molded shell made from post-consumer plastic waste: this is what the "2.0" in the color names refers to. The material is dyed throughout: a scratch will not reveal a different color underneath, and maintenance is limited to soapy water. On lighter colors, slight variations in shade are inherent to recycled material.

The swivel base: cast aluminum, polished or powder-coated

The base is a piece of cast aluminum—HAY writes cast aluminum swivel base—with four legs that fan out from a single center. The shell swivels on this base. The gliders are standard gliders, not casters: the chair rotates on its axis but does not roll on its own, making it better suited for a meeting or dining table than a workstation.

Two finishes. The polished aluminum is bare, shiny metal whose luster comes from mechanical polishing: it may show fingerprints slightly and can be revived with a soft cloth. The black powder-coated aluminum is finished with a baked-on powder: a thick, matte layer that is more resistant to impacts. HAY describes this base as having "a more formal expression" than the wooden-legged models.