The Eavesdropper's Best Friend

In my opinion, you don't need to spend tons (or any) money to be a good detective/spy. However, from time to time, I run across a gadget that seems particularly useful. Then I ask a certain friend to replicate it for me. (I'm feeling very thrifty these days.)

I recently found the "M-7 Secret Agent Spy Ear." Who knows if it works, but the manufacturer of this tiny device says it will allow you to hear other people's conversations across "great distances." They also claim you can "hone in" on specific conversations in crowded environments. Cool? Absolutely. Too good to be true? Possibly.