The extra small bag is about 7.5" x3" and is perfect for keeping all of my cosmetic brushes separate from the rest of my gear, in my toiletry bag.  I use a second one in my purse for keeping pens, tissue, earbuds, etc.

I've used Eagle Creek packing products for 15 years and have never had one fail me.  Well made zippers and smart design . . .highly recommended!