The operating instructions state: "The device is calibrated by the manufacturer for a period of two years. The metrological check must be carried out at least every two years in the case of commercial use. The check is subject to a fee and can be carried out by a competent authority or by authorised maintenance services - in accordance with the "Medical Device Operator Ordinance". The device is intended for safe use in accordance with its description for at least 10,000 measurements or three years. The cuff integrity is guaranteed even after 1,000 opening and closing operations of the closure."