Every person, before manufacturing or importing any weight or measure shall seek the approval of model of such weight or measure in such manner, on payment of such fee and from such authority as may be prescribed: Provided that such approval of model may not be required in respect of any cast iron, brass, bullion, or carat weight or any beam scale, length measures (not being measuring tapes) which are ordinarily used in retail trade for measuring textiles or timber, capacity measures, not exceeding twenty litre in capacity, which are ordinarily used in retail trade for measuring kerosene, milk or potable liquors: Provided further that the prescribed authority may, if he is satisfied that the model of any weight or measure which has been approved in a country outside India conforms to the standards established by or under this Act, approve such model without any test or after such test as he may deem fit.