Rule Book Question?

My understanding of the rules is that as long as you're battery is in the trunk it must be covered i.e. a battery box. I don't think it needs to be certified, the box me and a lot of people I know is just a basic marine box I got at like Gander Mtn. or Farm 'n Fleet. None of us have ever had problems, I think it has some vent slots on the top of it, it was only like $10 so I'm happy wit it