NoQuadsLeftBehind - that's a motto to live by, and a coupon code...buy 3 buzzers and get a discount with the code.
These ViFly's will scream like a demon if your battery comes unplugged. They replace your normal buzzer, and are significantly louder, but they also are self powered, so if your quad goes dead, the buzzer starts screaming until your reset it. I've found my quad underwater because they are screaming so loud. There's a strobe light included for finding it in the dark too....beeps for days so you can always come back in the mornign and try again!