Works well, I bought the pack for the jumbo size, to vacuum pack a memory foam mattress topper (queen size). Had to help compress it as the foam is 5cm thick and very, very dense. Have to make sure it's zipped up very well and keep rechecking as you suck out the air. I will definitely be buying these again. 3 days have passed with no signs of reinflation. Foam stopper isn't great quality, had to put my finger on it when I pulled away the vacuum hose, until I could screw on the cap. I expect the foam pad will compress or degrade eventually but we'll see. Screw cap completes the sealing process. Great value for the price, will update if it fails.