They tell the truth about these cases: they are thin, you have to tape them shut. However, I found them exactly as described by the seller. Honestly, it's still not worth pulling the mattress by the plastic bag, it will of course tear. There is enough space to make a valve and seal it with tape. I actually preferred it to a zip or whatever, the tape was much more secure. It catches easily and tears through the brackets on the box spring, so be careful.
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