Well, idk if these do but you can certainly make passive devices that penetrate walls. See http://en.wikipedia.org/wiki/The_Thing_(listening_device) http://en.

Well, idk if these do but you can certainly make passive devices that penetrate walls. See http://en.wikipedia.org/wiki/The_Thing_(listening_device) http://en.wikipedia.org/wiki/The_Thing_(listening_device)