Vahetatavat lisamõõtevahendit peetakse vahetatavaks, kui selle nimikarakteristikud on teada ja tähistatud ning piisavad selle mõõtehälvete kindlakstegemiseks asjaomast mõõtevahendit kasutamata.
An interchangeable accessory is considered to be interchangeable when its rated caracteritics are known and marked and are sufficient to enable its errors and variations to be determined without using the associated instrument.