law: Standards of Weights and Measures Act, 1976 
  38. Weight or measure
  
  to contain number of the approved model, etc.-
  Every weight or
  
  measure to which this Part applies and for which a model has been approved
  
  shall bear thereon, in such manner as may be prescribed, the number of the
  
  approved model and the number of the certificate by or under which such model
  
  was approved:
  Provided that where the Central
  
  Government is of opinion that inclusion of any such particulars on any
  
  weight or measure is not possible by reason of its size or nature, that
  
  Government may exempt the inclusion of such particulars on such weight or
  
  measure.