Using this for my mini bugout bag that I'm keeping in my car. It works great! It's a little smaller than I imagined, the picture makes it look wider than it is because it's taken from an angle. It's basically about the size of a hydration pack with a little more bulk.
This product is smaller than I expected; however, it is a well designed product. the G-Hook attachments make hooking to another pack's compression straps very easy. Additionally, these straps are designed to ALSO add compression to the pockets contents also -- very nice. Additionally, the shoulder straps (1" wide) have a nice pocket for storage and will be helpful for a short trip; but with heavy loads... not recommended. The bag also has a thin plastic liner to add form. It covers the back side and wraps to the front around the bottom.
I have Deuter side pockets for my packs also and one of those is almost as big as this one bag.
Took one star because it should have been a llittle bigger than it is -- say 2 - 3 inches wider.