I purchased these compression packing cubes thinking they would really compress my items. I have those clear plastic ones that you squeeze the air out of and they do an amazing job of compressing things. However, these cubes really don't compress items very much. Mostly, they just flatten the edges of the cubes by where the outside zipper is. The center of the cube stays pretty much humped up at the same thickness as it was before. So, essentially instead of having square edged cubes you have rounded edged cubes. It really doesn't save that much space when packing. Also, zipping the compression zipper is time consuming because you have to be careful not to catch the extra fabric in the zipper all the way around...slow going. I don't see myself bothering to do that very often. In summary, I think regular packing cubes are just as good as these and if I really want to save space and pack a lot in minimal suitcase space, I will use the plastic compression bags that eliminate the air in the bag.