If you are looking for a dual battery box for your 6 volt golf cart battery mod, I highly reccomedn this one:
It fits just about perfectly. I just put a cut piece of 1/2 ply that I sprayed with rubberized coating in the bottom of the battery rails and screwed it down. This photo doesn't show it, but I modified an 800 pound ratchet strap to hold down the box just in case.
You can get it from shipped to your door for around $60
http://www.allbatterysalesandservice...cfm/4,576.html
Ed