67.—(1) Weighing instruments used in any of the following transactions, that is to say, transactions—
(a)in gold, silver or other precious metals,
(b)in precious stones,
(c)in jewellery,
(d)in silk,
(e)by retail in drugs or other pharmaceutical products,
shall either—
(i)be balances, or
(ii)being instruments other than balances, fall within the prescribed limits of error for beam scales marked “Class B”.
(2) Weighing instruments used in retail transactions in tobacco shall either—
(a)be balances, or
(b)being instruments other than balances, fall within the prescribed limits of error for beam scales marked “Class B” or “Class C”.