The halfpennies of King James II (1685–1688) were made of tin with a small square plug of copper in the centre. The corrosion properties of tin mean that very few coins survive in a good state of preservation, not helped by the electrochemical reaction between copper and tin. The objects of using tin were to produce coins at a profit while at the same time producing a coin which would be difficult to counterfeit, and at the same time to assist the ailing tin-mining industry. The coins weighed between 10.5 and 11.6 grams, with a diameter of 28–30 millimetres. The obverse showed the right-facing effigy of the king with the inscription IACOBVS SECVNDVS – James the Second – while the reverse shows the same Britannia as before. Unusually, the date appears not on the reverse but on the "edge" of the coin, which has the inscription NVMMORVM FAMVLVS date – "an ancillary coinage". The coins were produced in 1685, 1686, and 1687.