I picked up this first aid bag from Sportsman's Guide to put in the jeep. It's a Swedish kit and comes with some nice stuff inside. I like it because it has a belt loop but can be detached. I wanted something on the jeep fairly small and out of the way but functional. It measures approx 12" high, 6" wide and 4" out if loaded all the way. It has some nice pouches and is waterproof with top overlapping body.It fits nice behind the seat and won't interfere with the half top that I envision jeep having on most of the time (one day)

This is final set up with strap to keep it close to seat and not swaying to and fro

Those buttons press on the belt and just pull off if you need it detached, similar to lift the dot fasteners

I used what I call Chicago fasteners to keep it smooth and not snag on cushion, belt at top and 1 for nylon strapping

10/32 machine screws oval head and cup washers
