comprise slack wax (as to approximately 58 to 59% of the total weight), and hardwood sawdust (as to the remaining weight);

were manufactured from those constituents by a process of heat treatment and extrusion;

are approximately 265 millimetres in length and 80 millimetres in depth, with grooves along their faces;

have an average weight of 1.3 kilograms; and

have a sulphur content not exceeding 0.1% of the total weight.