I bought these to use when we spent two weeks in Alaska.  I bought a backpack and stacked three of these cubes filled with an extra set of clothing and items in case my luggage was lost-- and it was.  I loved the fact that I could just stack them.  They also helped keep my clothes organized.  Perfect for a back pack, but I'll use them in a suitcase, too.  Takes the mess out of traveling.  Excellent quality and the size was great.