I remember seeing them on an infomercial about 10 years ago. Zip + shop vac.
Never used them for shipping, but have used them for storage. Most of the various brands of these I tried out only held vacuum for maybe 5 days. Once in awhile they held vacuum for a month, even when we were as careful as possible to make the ziplock tight and uniform. In the end I had to use a thermal sealer, which made them a 1 time use which for storage was a bust, but if you’re just looking to seal and ship might work for you.
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