Aluminum is an armchair designed by Mats Theselius in 1990 and produced by Källemo. The armchair, as the name reveals, is made of aluminum and is available in either a polished or matte brushed finish. The seat is covered in a core leather from Tärnsjö Garveri and can be chosen in several colors. The back is padded 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 highly sought after worldwide.