1.1 This part of ISO 6916 classifies flexible cellular rubber products known as sponge and expanded rubber. The base material used in their manufacture may be natural rubber, reclaimed rubber or synthetic rubber, either alone or in combination. The only products included in this part of ISO 6916 are in the form of sheeting. 1.2 This part of ISO 6916 does not apply to latex foam rubbers, shoe soling or other similar micro-cellular products, ebonite cellular rubbers, virgin or reconstituted flexible, semi-rigid urethane foams, virgin or reconstituted poly(vinyl chloride), or poly(vinyl chloride) blended with other polymers.