60. Taybrite briquettes (otherwise known as Surefire briquettes), manufactured by Coal Products Limited, Immingham Briquetting Works, Immingham, North East Lincolnshire, which—
(a)comprise anthracite (as to approximately 60 to 80 per cent of the total weight), petroleum coke (as to approximately 10 to 30 per cent of the total weight) and a molasses and phosphoric acid binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing and heat treatment at about 300°C;
(c)are pillow-shaped briquettes marked with a single indented line running longitudinally along each face, offset from its counterpart by 10 millimetres or unmarked;
(d)have an average weight of 80 grammes per briquette; and
(e)have a sulphur content not exceeding 2 per cent of the total weight.