The EAR-2000 (Bomb Detector) will listen to virtually any surface with the built-in contact element. Simply place the contact against the surface to be tested (metal, air ducts, plumbing, conduit, windows, etc.). The internal automatic gain control will deliver clear, undistorted sound. The EAR-2000 can be connected to any standard tape recorder. The recorder output can also be used with audio spectrum analyzers and other measurement equipment for detailed analysis.