We have the whole assortment of Eagle Creek (EC) gear/cubes.  I use the half-cube for my undergarments; DH uses his to pack his big-man adult socks; and I got these for my niece & nephews and they pack their little shirts.  When travelling, the cubes help keep everything in its place, making things easier to find and pack.

The gear itself is washable (I'd recommend cold & line-dry).  However, it seems that EC discontinues their colour scheme within a year or so, so if you wish to purchase a set, don't do it over time; make sure you get it all within a couple months.  A lot of other websites don't offer discounts on EC gear, so with Amazon's Prime free shipping, I usually end up buying their stuff here.  =D