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.
ANSI/ASTM Class 4 Calibration Weights - For calibration of semi-analytical balances and for student use. ASTM Class 4 calibration weights and weight sets should be used in simple weighing environments and for educational purposes. Class 4 weights can be used to calibrate precision balances, Class I and Class II laboratory balances and digital scales. Class 4 weights are equivalent to OIML Class M1 weights.