Class E1 weights intended to ensure traceability between national mass standards and weights of
                a lower accuracy class.

Class E2 weights intended for use in the calibration of weights of a lower accuracy class and for
                use with weighing instruments of special accuracy class I.

Class E2 weights or weight sets have to be accompanied by a calibration certificate.

Class E0, E1 and E2 weights can be supplied either individually or in sets (plastic or wooden case)