comprise slack wax (as to approximately 55 to 60% 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 255 millimetres in length and 75 millimetres in diameter, with grooves along one longitudinal face;

have an average weight of 1.3 kilograms; and

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