In addition to the very well made and expensive Blue Sea battery boxes for 8D's Google found some much less expensive alternatives including Todd, Tracy and Midstate Snap-top. There are some boxes large enough to hold two 8D's and the prices are much less. I suspect they are not very structural but would serve to contain acid spills and to cover and protect the battery terminals. These are probably similar or equivalent to the ones Greg McKay bought for $40 CDN. Arild, what is your opinion about the "bubble" in the top of the battery box? Do you recommend vents in the box top, no vents or do you think it is not important either way? I was in the process of building a custom box but might just buy one of the Todd or Tracy boxes. Thanks Jim Fidler "Fiddlesticks"