Zeolites, by definition, can be natural or synthetic, but they are always crystalline aluminosilicates.  Zeolites contain definitive porous structures made of uniform pore sizes.  These pores create a framework of sites that molecules of a given size can be 'trapped' in, i.e. a water molecule in a 3 Angstrom pore.

Molecular Sieves can be made from Zeolites, but they also be made from carbon, silica gels, or porous polymers of infinite composition.  However, most Molecular Sieves are made from aluminosilicates or Zeolites, and the name infers that the material is able to seperate different molecules based on size.  Basically, the name describes their function which is "sieving".

ALL of our Molecular Sieve Solvent Pouches use synthetic, virgin, aluminosilicates or Zeolite with a specific 3 Angstrom pore size to extract unwanted water from solvents used in oligonucleotide synthesis.

In conclusion, our Molecular Sieve Solvent Pouches aka molecular water traps, trap packs, water traps, etc. use Zeolitic Molecular Sieves to quickly and permanently eliminate water from solvents.