4. Ancit briquettes, manufactured by Coal Products Limited at Immingham Briquetting Works, Immingham, North East Lincolnshire, which—
(a)comprise anthracite (as to approximately 60 to 95% of the total weight), petroleum coke (up to approximately 30% of the total weight), bituminous coal (up to approximately 15% of the total weight) and a molasses and phosphoric acid binder or an organic 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 unmarked cushion-shaped briquettes;
(d)have an average weight of 48 grams; and
(e)have a sulphur content not exceeding 2% of the total weight.