[0.145 lb] Small - fits 8 shirts
Xsmall - fits 7 underwear
Xxsmall - no idea yet what to put

[Universal] Peak design makes wonderful accessories, and has wonderful customer service, in my opinion. This item turned out to be a bit large for my backpack, so I ended up returning it.

[Sage Green] I used to throw all by bathroom/toiletry items in one big bag, and every night I had to dump the bag. I’ve bought an XS and XXS cube - they will be great for differentiating and organizing. One cube is mesh so anything that might be wet can breath. I’m thrilled to have them, and expect more will be added.

[Zipper] I love the new eclipse color! I really hope you make some of your other bags with it! As far as size, the Small is perfect for a pair of men’s pants rolled up and maybe a couple t-shirts. Which is great for spare clothes when on a two or three day hike. Also great for an extra couple shirts and socks in your carry-on. The XSmall bag is perfect for organizing 8-10 thin socks.

[Universal] ...when they fit your use case, they are absolute worth it! For me, the ultralight packing cubes are exactly what I needed. I own a 30l everyday backpack, and they fit like a glove. The regular packing cubes sit a bit too tight, if you tend to use the backpack's flaps side pockets. These don't. Three of them easily stack, four, if you force it. With my camera, an extra lens, tech pouch and toiletries, two of them fit on top. To put it in perspective, I can fit t-shirts, undies and socks for four days into one cube (s). That leaves another for a light sweater and some pants. But the real game changer is, that 1 the cubes are waterproof and 2 the passthroughs on the sides. I don't mean the loop, I mean the passthroughs where the fabric foulds and is stitched together. Because this way, you can pass the lower external straps of the everyday backpack though and put one cube under the backpack, without dangling around, like it would do, if you'd use the loops. It sits tight underneath the backpack. That expands your space by easily 6 to 10 liters!
That's why I always carry one of those cubes in my backpack. If I should shop groceries and need more space, I can expand my capacities on the fly. I love it!

[Empty] I've bought 3 black ultralight packing cubes. Sizes: Small | XS | XXS. They are indeed featherlight, since they weigh in at 43 g | 27 g | 20 g. The bags are not see-through which is great for taking it out. i will use them for packing and hiking. For my fellow Eastern European buddies, the small bag will fit a full adidas tracksuit and a book. For all other people this means it will fit two average size shoes (mine are 43 EU, still fits)

Very easy and simple design, yet sturdy. overall happy.

[Empty] I commute in my bike a lot, and during the hot months I end up carrying extra shirts, deodorant, bug spray and a bunch more doodads that usually just bounce around in my backpack.

I bought three of the UL Packing Cubes and I can chuck everything that's loose and carry it more comfortably. And what's best is that attaching an external strap makes it the perfect carry solution for simple walks when I just want to bring my phone and sunglasses and don't need a whole bag.

Materials are quality and the eclipse color is beautiful.

[Sage Green] I love my xs packing cube, it fits in my everyday carry bag and is always ready to put my valuables in to keep dry when I get caught in a downpour while commuting on the bus.

[Sage Green] life savers, no less! have had many packing cubes over the years, these by far exceed anything else. right now on a long trip- constantly packing and re packing, forwarding luggage. the cubes make this so much easier!

[Zipper] I bought three of these in XXS and XS sizes. I planned to use them for cords, meds, and other small misc items when traveling. I’ve found myself reaching for these bags for every day use also. Great to put some small gear and toss in the daypack when out photo-hiking. Also makes a good wet sack for my bathing suit. I can think of so many uses for these bags. They are well made and roll up very small when not in use. Great that they can clip to a belt loop or another bag, or be used with a strap.