I use a marine case for my trunk mounted battery. But I also have a sheet of 1/8" thick metal right behind the rear seat back so it closes and seals the trunk off from the interior which is needed by the rules anyway. I drilled a few holes in the bottom of the box near the four corners that just go thru to the outside under the car to vent the battery. Works fine for me. I like the metal battery boxes that Jegs and others sell but I got this marine battery box free as the metal ones are not cheap as I believe they are over $100 dollars. But the metal ones are really nice. You can see the rod for the cutout switch also as the cutout switch is bolted to the battery box and I drilled a hole in the taillite lens to go thru to the outside. That way the only thing it changed was a small hole in the lens. If I ever took it out all I have to do is put a new lens in. Ron