Interior architect Olli Mannermaa (1921–1998) had a long career with Tehokaluste, which is now Martela. Mannermaa is known particularly for his Kilta chair, which he designed in 1955. At the time of its creation Kilta was a ground-breaking chair, as its frame was cast out of a single piece of expanded plastic. Kilta is still in production, and the chair is part of the collections of museums such as MoMA in New York.