40. Supertherm briquettes, manufactured by Coal Products Limited, Immingham Briquetting Works, Immingham, North East Lincolnshire, which—
(a)comprise a blend (in the proportion of 19:1 by weight) of anthracite and medium volatile coal (as to approximately 93 per cent of the total weight) and a cold-setting organic binder or a molasses and phosphoric acid binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing;
(c)are unmarked ovoids;
(d)have an average weight of 160 grammes per briquette; and
(e)have a sulphur content not exceeding 1.5 per cent of the total weight.