Aluminum is an armchair designed by Mats Theselius in 1990 and produced by Källemo. The armchair, as the name suggests, is made of aluminum and is available in either a polished or matt brushed finish. The seat is upholstered in a core leather from Tärnsjö Garveri and can be chosen in a number of colours. The back is upholstered with cold foam and the seat in cold foam and Dymetrol. The chair frame can be matched to the upholstery as desired and is available in natural beech, alternatively in black or walnut-stained beech.

Aluminum is part of a series of products that many call Theselius armchairs, where the common feature is the use of larger pieces of metal combined with leather. This combination makes the armchair as elegant as it is industrial in its look. Theselius chairs are today very sought after worldwide.