2. Aimcor Pureheat briquettes, manufactured by Applied Industrial Materials UK Limited, Immingham, North East Lincolnshire, or manufactured by Oxbow Carbon & Minerals UK Limited, Windsor House, Cornwall Road, Harrogate, North Yorkshire, which—
(a)comprise anthracite (as to approximately 60 per cent of the total weight), petroleum coke (as to approximately 25 per cent of the total weight) and binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing and heat treatment at about 250°C;
(c)are pillow-shaped briquettes with a single line indentation on one side and a double line indentation on the reverse side;
(d)have an average weight of 75 grammes per briquette; and
(e)have a sulphur content not exceeding 2 per cent of the total weight.