1. Green rectangular mark that meets the specified requirements, the instrument is qualified. Used for qualified measurement equipment, fill in the content generally include the number, effective date and verification of the person and so on.
2. Yellow rectangular mark that part of the function or range to meet the requirements, allowing some limited use. Used in the approved degradation of use or limited or temporary use of measuring equipment, fill in the content for the number, seal date and verification.
3. Red rectangular mark that does not meet the requirements, unqualified, not allowed to use. Used for the approval of unqualified measuring equipment, fill in the content for the number, date of disable and certified.