We've always loved packing cubes for a well-organised suitcase, but they come at a cost of taking up added space in your suitcase. Eagle Creek decided to try and combat that problem by adding a compression zipper to their ultra-thin line of packing cubes. The result? You end up with vacuum-sealed-like package that takes up less space.
I used these to pack my last suitcase for a recent trip to our New York HQ. To add to the challenge, I chose my smaller weekend bag and had to fit eight days worth of stuff. I've always loved the challenge of fitting a lot into a small space and packing prudently to avoid taking things I don't need. I was able to compress the cubes enough to fit a blazer and a few other chunky items that I otherwise would have had to leave at home.
They work best if you put less in them, obviously. The compression technology will function regardless of how much you stuff inside the cubes but they tend to get a little bulbous if you really make use of the space. Nevertheless, you do save some space regardless. I just had a little trouble fitting nine pairs of socks (you know, because you always take an extra pair) into the tiny cube. The cubes are made out of very thin material so they don't add much weight. Definitely worth investigating if you're a frugal packer.
Pack-It™ Specter Compression Cube Set [Eagle Creek]