I already have a 12V LED fixture in that tank and there are AA battery packs at the local hobby shop for that (9V or chain 2 6V), It's also not like I can't find a couple low voltage ones and use a small C or D holder like I already have for those, no special batteries required.
Simplemente. I have lots of stuff like that.
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I don't know nothing, and I memorized it in school and got this here paper I'm proud of to show it.