It's a power source? [That's his best guess, anyway. He's never heard of electricity, or furries for that matter, but he's more interested in the former. He leans close, peering at the charging device]

So the ears help you hear, and they're powered by the... battery? I've made uh -- braces, mobility aids before, but never anything for ears. My mom has prosthetics for her hand, for instance. And -- [He gestures to his own leg brace]