I'm so bummed that every single bag I used let the air back in almost immediately. I wanted these bags due to the size. I needed larger bags. The jumbo bag is enormous which is just what I needed for comforters. However, checking the bag a few days later, it was no longer vacuum packed. So I checked the large bags I had packed other things in and they too were no longer vacuum packed. One bad feature of these bags is a screw on cap. The cap comes off so after sucking the air out of the bags, you have to quickly put your finger over the hole and screw the cap on while trying not to let air in. Horrible design. I'll stick with space bags. They've never let me down.