law: Standards of Weights and Measures Act, 1976 
  25. Preparation and
  
  custody of secondary or working standards. –
  The Central Government
  
  shall cause to be prepared, for the purposes of this Act, as many sets of
  
  secondary standard or working standard as it may think necessary and shall keep
  
  such sets of secondary standard or working standard at such place and in such
  
  custody as may be prescribed.