The accuracy class for weights used as standards for the verification of weights or weighing instruments should be in accordance with the requirements of the relevant OIML Recommendations.

The letter “E” for Classes E1 and Ez refers to EXTRA FINE where the letter “F” for Classes F1  refers FINE.

The Class F1 weight bear number indicating the nominal value, but E1 & Ez unmarked. Duplicated weights are marked with a dot and weight composition is according to OIML recommendations mainly 5-2-2-1 composition.