This is a remix of a battery holder I downloaded quite a while ago. I don't recall where I got it, but it is not my original design. I just changed it from a standard screw/wall mount to work with the multiboard system. You can use a Big headed big threaded bolt, or choose to use my custom big headed, big shouldered medium bolt that is also on Thangs. This holds 2 Bauer (Harbor Freight) batteries.