Corallis,

The hidden compartment is at the very bottom of the pack. It's about 2 to 3 inches in height and the top and bottom inside surfaces are lined with velcro. The pack comes with a nylon thumb-snap holster and spare magazine carier. These are covered with velcro and can be positioned to your preference inside the compartment. The compartment is designed so that the handgun lies parallel to the bottom of the pack.

Access to the hidden compartment is via a flap that rests against the small of the back when the pack is worn. The flap is secured with velcro. To access the weapon, you would reach behind your lower back and tug the flap open. When closed, the flap looks like a section of the padded back.

The main compartment is subdivided by a panel that runs along the back surface. Two of the outer pockets are also subdivided. One has an organizer panel, the other has two elastic mesh slots. There are also a couple of flat velcro panels - one inside the main and the other in an outer compartment. These can be used to attach anything made of velcro.

The Demon is a very cleverly designed pack. I'm very happy with mine.

I hope that this all makes sense - I'm on pain meds for a back injury.
I'll be happy to answer any other questions that you may have.

Steve