57. Maxibrite briquettes, manufactured by Maxibrite Limited at Mwyndy Industrial Estate, Llantrisant, Rhondda Cynon Taf, which—
(a)comprise anthracite fines (as to approximately 84% of the total weight), petroleum coke (as to approximately 12% of the total weight) and starch as binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing and heat treatment at 250°C;
(c)are cushion-shaped briquettes marked with the letter “M”;
(d)have an average weight of 35 grams; and
(e)have a sulphur content not exceeding 2% of the total weight.