61. Therma Briquettes, manufactured by Maxibrite Limited at Llantrisant, Rhondda Cynon Taf, South Wales, which—E+W+S
(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 oval or tear-shaped briquettes with a line through the centre;
(d)have an average weight of 26 grams per briquette; and
(e)have a sulphur content not exceeding 2% of the total weight.