Molecular Sieve, 3A, 4A, 5A, 13x molecular sieve etc. Detailed Product DescriptionA molecular sieve is a material containing tiny pores of a precise ... and uniform size that is used as an adsorbent for ... and water can diffuse.CHEMPACK supply five types of molecular sieves: 3A, 5A, 6A, 13X(10A), Cu-13X. 3a Molecular Sieve