ST10 has a backrest, that is springy. Using a principle from the ski industry.
The ST10 is based on the principle of sandwich technology, a concept from the ski industry. The back legs have an aluminium-reinforced cover glued to a high quality wood composite core. This provides higher resistance to mechanical pressure and better tensile strength than conventional structures. The top of the back legs tapers to just 8 mm, giving the back a filigree look and a light springiness. Combined with the minimalist basic design, this creates an unusual, extremely strong and comfortable stackable chair for design-oriented furnishing.