I have one of these I use for sealing up partially used hops... I keep them in their orig packages and then seal them up in these bags. One thing you have to do is where the device 'connects' to the bag... has to be flat... can't be anything around it. If you notice in the pic of the link you have, the meat comes right up to that port, thats what you have to do with anything you put in it. I found its easier to put the 'stuff' in the bag, start to seal the ziplock, push as much air out as possible, finnish zipping it then seal it up with the vacuum.