Proving Pieces, Royal Mint, London, Plating Trial, c. 1970, in conjunction with the British Steel Corporation, in chromium-plated steel, crowned arms dividing Tower Mint logo and a rose, royal mint on banner below, trial to left of crown, rev. hour-glass shaped flask, b s c to left, c r 17 to right, edge grained, 23mm, 4.97g/6h (cf. Tansley 475). Extremely fine; the best of the two specimens believed extant outside the Royal Mint £80-100