I received several jumbo space bags in the mail as a sample to try a while back. Since we were going to be moving, I thought these would come in handy to store our big bedding & pillows since they take up so much space.
I followed the directions on the packaging very carefully and at first the space bags seemed to work really well. Using my vacuum, I sucked out a great deal of air and it took a huge bag filled with my bed comfortor & pillows and shrank it to where I could easily fit it inside a box. Well, I set the bag aside so that i could continue my packing and within a few hours, the air had completely refilled the bag and i was back to where I started.
I tried sucking the air out again but it only lasted for a short time. Finally, I sucked all the air out, then got some clear masking tape and taped shut any area that could possibly leak. Within a few hours, all the air had still somehow gotten back in.
Basically, in my opinion, these things don't work worth a flip and had I not gotten one as a free sample, I would never ever waste my money on these.