All parts coming in contact with the stored medium are made of DIN 1.4571 stainless steel. All parts not coming in contact with the medium, such as strengthening ribs and binders, are made of DIN 1.4301 stainless steel. The hand wheel is made of aluminium. Bushings and hinge bolts are made of cast copper. The concrete cast parts are made of DIN 1.4301 stainless steel.