42. Thermac briquettes, manufactured by Coal Products Limited at Immingham Briquetting Works, Immingham, North East Lincolnshire, which—
(a)comprise anthracite (as to approximately 90 per cent of the total weight) and cold-setting organic binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing;
(c)are unmarked pillow-shaped briquettes and have an average weight of 48 grammes; and
(d)have a sulphur content not exceeding 1.5 per cent of the total weight.