The reason why I don't need the height adapter on mine may be that the rods for securing the battery are tall and one has worn a hole through some of the hood insulation. They're longer than necessary and the threads go down far enough on the rods that I don't need the adapter. Maybe at some point something else was in there and the bracket I have isn't stock.

P.S.- Someone brought this up before, but I'll reiterate - get one of those things you can plug into a cigarette lighter and you won't lose station presets when you fiddle with batteries. Just snap on a 9V battery and plug it into the lighter port.