HAWKUNG 20 Pcs 3D Printer Filament Vacuum Compression Reusable Storage Dry Bags with Double-Layer Zippers for Filament Storage, Compress and Remove Air to Prevent Humidity in Filament, 30x34cm

Pumping air out is extremely difficult - the air valves rarely open correctly. Bags tear easily.

I saw some bad reviews of these and compared to my experience they are unfair.You do need to lay the part of the bag that you push the pump up against flat on a hard surface. That's not a bad thing, it's how they work.All of my reels fit inside, they come with a load of those gel bag things and you can suck nearly all of the air out of them easily.What more could you want from them?

This actually works really well. I was a bit confused that you just place the nozzle over the sticker on the bag and don't peel anything off, but after a few pumps the bag shrinks up brilliantly and holds the seal really well. Such a strong vacuum that it actually can bend the plastic of the spool, so be careful!

When you use the pump it seems like it can't possibly work, but having read another review I persisted and it worked perfectly. So for half a dozen pumps it seems like you're wasting your time, then it suddenly kicks in and everything is fine.

I got these to store other things as it says that you can like herbs coffee beans ect, the air is pulled out brilliant but the bags are not so vacuum packed just a few hrs later so I feel the seals are not the best. I have tried 3 bags and keep persisiting since Friday but have had to pump air out every day so far. Feel the bags may be faulty and can't find out how to message the seller as yet