1.1 This specification covers flexible cellular rubber products known as sponge rubber and expanded rubber, but does not apply to latex foam rubber or ebonite cellular rubber. The base material for an This specification covers flexible cellular rubber products known as sponge rubber and expanded rubber, but does not apply to latex foam rubber or ebonite cellular rubber. The base material for an open/closed cellular product may be made of synthetic, natural, or reclaimed rubber, or a mixture, and may contain other polymers or chemicals, or both, which may be modified by organic or inorganic additives. The cellular rubber shall be categorized by types, classes, suffixes, and grades: Types 1 and 2; Classes A, B, C, and D; Grades 0, 1, 2, 3, 4, and 5. The various grades of cellular rubber shall conform to the requirements as to physical properties specified. The following test methods shall be performed: accelerated aging tests; compression-deflection tests; oil-immersion test (open-cell sponge); fluid immersion tests (closed cell); water absorption test; density tests; and low-temperature flex test.