The small pocket on the outside is for an MP3 player, I use it for my cell phone. There are also two compartments on the outside by the waistband, one on each side, I keep my food and snacks in those. I can tell you an XD sub-compact will also fit in one
The inside also has pockets, some that zipper. I am on my way to work, but will take some more pictures when I get home.