I love mine. I might still have the dimensions somewhere, but I know it was 43" wide and 7.5" high. If I had to do it again I'd make it about an inch higher. I have a hinge in the middle so I can lift it up and easily reach stuff inside. On one trip I got stuck and the rear end was pretty deep in mud. I didn't want to walk through mud to get my tow strap and open the hatch. I was able to get into the back seat, open up the hatch on my box and get the strap since it opens up that way.
I liked having the end open so that if I do have stuff packed on top, I can reach in still and pull out whatever I need without having to move anything on top.
I stapled a rubber matting on the top to protect the wood some as well as making it easy to wipe off mud and water.
I have latches on the sides so when I go wheeling, I stick a bolt or anything in the latches and it locks them down, so stuff doesn't go flying around. It's strong to support all of my stuff when I pack my XJ to the top with gear.
For securing it, use the 4 metal rings on the floor and put a bolt through the rings and through the side panels. If you ever need to remove the box for cleaning or whatever, take out the bolts and out comes the box.
Here's what I keep inside:
Two jackstands
4 ton jack
120 piece socket set
grease gun
battery charger
all recovery gear (snatch block, 2 straps)
basic hand tools (screwdrivers, knives etc)
18V drill and bits
angle grinder
gloves
spotlights
cords cables, torque wrench and other stuff
I have since added a panel on the open end that is removeable. When I went wheeling, stuff could slide around and when I opened the hatch it fell out. I put two double threaded screws on each side and put a board that slides over the screws. A few wingnuts and it's secured on there. If I need to get in there, it takes about 10 seconds to undo the wingnuts and come off. With the board on there it's a fully enclosed box. I can take more pics if you'd like to see what I'm talking about.
Chris
I think the main thing to think about is: can i access it several differnt ways? Is it easy to get to stuff in the back as well as the front?