1. Definition To determine the difference between the reading to the correct value.

2.  Corresponding to a standard of measurement  Due to the change of scales and weights.  To be able confirm the accuracy of the measurements. -Know the limits tolerances of the measurement results or not. - A few percent certainty that the measurement results. The tolerances in scope. - There is a reference or not. - Confirm it possible that the accurate suitable for work  The Preparation of quality system

4.  OIML (International Organization of Legal Metrology) OIML R111 divided by weight into Class E1, E2, F1, F2, M1, M2, M3.  By technical specifications of the weights.  Shape  Material  Magnetism  Surface condition  The error of weights (Error).

5.  Stainless Steel  Class E1  Brass  Class F1  Recommend F2  Steel  Class M1  Recommend M2

6.  One piece

9. From the ISO 10012, we have to choose Tum weight Not more than the tolerances. 1 in 10 of tolerance, but tolerance is deferred to. Up to a maximum of 1 in 3.  For example, if we want to calibrate weights 100 g by the coordinates.  Error does not exceed ± 0.15 mg, so the weight of the calibration standard.  To deviate by no more than 1/3 of 0.15 mg, equivalent to 0.05 mg.

11.  Do not touch the weights with bare hands.

12.  Cleaned using a soft brush dusting particles.  Keep weights In clean area environment and a constant

13.  Do not place the weights on the floor directly or place the weights stacked

14.  Keep weights knocked crash or dragging to the weighing pan.