Bats use echolocation to navigate. This bat detector will give you a look inside their hidden world and can even be used to identify different species.
Build a Simple Bat Detector
Vampires Bats and a Bat Detector
Magenta Bat 4 Bat Detector: NHBS today's purchase!!!
Bat Detector: Listen to the Secret Sounds of Bats
Build an Enhanced Simple Bat Detector - Parts List