Calibration Weights are used to check the reading of scale, to make sure it is still accurate. They used when calibrating a scale.
While the calibration states how a scale behaves, adjustment of the scale changes its behavior. What it dose is a set of operations carried out on a scale so that it provides prescribed indications corresponding to given values of a quantity to be measured.
Therefore, adjusting a scale means modifying its indications in a way that allows them to correspond – as much as possible – to the quantity values of the measurement standards applied.
Class E2 - OIML Class E2 Weights manufactured to international recommendation, OIML R111 specifications would be used to calibrate Class I/II balances, balances accurate as 0.001mg, and as a laboratory standard. These classes are considered to be of extra-fine accuracy.