I was really excited to take these compression cubes on a trip. Unfortunately, four out of six of them had their compression zippers catch on the bag material and get stuck, BADLY stuck , no matter how carefully I zipped them. Neither I nor my stronger friend were able to free them, even with pliers. So I can't even use them as regular packing cubes anymore, since they got stuck in a half-compressed state.
If you buy these and never compress them, you can use them as normal packing cubes. But the zipper compression design seems to have this fatal flaw if you want to try to compress them.