The Standards of Weights and Measures Act,1976
Section 27. Secondary or working standard, which may be stamped
Where the Central Government is of opinion that by reason of the size or nature of any secondary standard or working standard referred to in Sec. 25, it is not desirable or practicable to put a stamp thereon, it may direct that instead of putting a stamp on such secondary standard or working standard, a certificate may be issued to the effect that such secondary standard or working standard conforms to the standards established by or under this Act and every secondary standard or working standard so certified shall be deemed to have been duly stamped under this Act on the date on which such certificate was issued.