2.0 to 2.8mm molecular sieve 10 years experience for 3A, 4A,5A, 13X drying,absorbent,cleaning ect. ISO9001:2000 product2. ... 0 to 2.8mm molecular sieveProduct descriptionMolecular ... (as when used in dehydration), or heating under high vacuum.3A (pore size 3 Å): Adsorbs NH3, H2O, (not C2H6), good for ...