I went with the DEEZEE narrow plastic rail mounted. The number embossed on the inside of the lid is PN DZ6170P.
We were in our local Princess Awful store and I saw this box on the high top rack that looked interesting with a regular price at $249can. Told the wife I'd like them to bring it down for a closer look. She says why? That's the one over here for $75. Bonus...good wife.
I tell ya I should have bought all of them. Perfect size for the 5 foot truck bed and well made.
In the pics you can see the cylinder lock dust cover I added.
I also didn't like the way the 2 J-bolts provided only held it down with a flat, lock washer and nut in 1 location per side through the weaker flat portion of plastic. I cut a short length of 4" ABS pipe to fab 2 segments about 3 1/2" along the radius. Now the bolt clamps down on 2 stiffener ridges on the horizontal and vertical
planes.
I'm a very happy camper with this box.