HFS(R) Molecular Sieve 3A Zeolite 8X12 Mesh Desiccant Beads Reusable 500G

This worked great for me. I found that it needed activating before use- it's shipped sorta semi-hydrated. Just roast it over a flame in an appropriate steel or glass vessel. I cooked mine for about 4 hours but i bet less will work nearly as well. I've heard they can be microwaved too but i haven't tried it. You can test them by putting half a teaspoon of room temperature product in your palm and drip some water on it. If it's ready to use they'll get real hot real quick! Enjoy.

A must have in any lab, great for drying solvents

Came in a vacuum sealed bag, which is a good sign of quality control. After the first use, the bag will be torn, so it will require to be stored in a glass jar away from atmospheric humidity.

Product came vacuum sealed in an aluminum foil package inside a yellow padded envelope which was sufficient for the purpose. The Molecular Sieve does an excellent job of removing water from Ethanol and are very easy to reconstitute for reuse by simply rinsing in warm water then bake dry at 200° for about 30 minutes spread out on cookie sheet and its ready to reuse.

Good product. It would however be nice to have a resealable package since they are reusable.

Works great, good packaging, fast shipping. I couldn't ask for any thing else!

I've found these ineffective so far in drying ethanol, which is my primary application. They seemed to come out of the bag (foil lined plastic vacuum packed) completely inactive. After numerous less drastic measures, the last activation recipe I tried was putting them through the short cleaning cycle in my oven .... This is ~750F for 2-3 hours. After that they seemed bone dry in the microwave and under 0.05 atm I got zero condensation. When added to alcohol-water mixture they warm very slightly and do little if anything except leave less liquid. Maybe they are 5A sieves? The 4A sieves available from a different seller here in "jugs" have dried EtOH very well for me, to >99% (volumetric flask + analytical balance). I think that this is because water is (strongly) preferentially taken up as it is a smaller molecule than EtOH. They get warm, or quite warm, as expected. I'll update this later if I figure out what's going on but right now they seem to be a relatively expensive gardening material.

Very nice. Absorbs lots of water and the enthalpy of absorption is obvious, it heats up pretty good.

Can in a blank grey sealed bag, the weight was accurate. If it doesn't work as expected I will update the review

I use these for my 3D print filament storage to keep them dry. Works verywell. My AMS stay at 5% humidity all the time. The best part is you reuse them after using high heat to dry them out. Good buy.

Had to change it multiple times, as it removed water quickly, and stops when saturated Very good product, easy to wash and reuse

Exactly as described. Arrived in heavy vacuum sealed foil bags, albeit one of them was a super wonky shape. These things suck the air dry down to single digits RH and keep it there for considerable time. Used for filament drying and storage for 3d printing. Worlds better than silica gel. I've yet to try to recharge them.

Oh, how wonderful. I ordered molecular sieve desiccant, expecting it to, you know, be ready to adsorb moisture right away. But what I received was already nice and saturated – pre-loved, if you will. Thanks to this brilliant surprise, I got to spend quality time regenerating it in the oven before the first use. Truly, who doesn't enjoy an extra chore? It really adds value to the purchase. If you're the kind of person who likes to wonder whether your desiccant is actually desiccating anything at all, this product is perfect for you. Highly recommended for people who have too much free time and enjoy guessing games.