Scientists are developing radar flashlights that would see through doors and walls. The device developed at Atlanta's Georgia Tech Research Institute, USA, can detect a stationary human's presence through solid wood or a 20 cm block wall from nearly 1.2 m away. The flashlight uses simple microwave technology. It emits an invisible beam of electromagnetic radiation one-tenth as strong as the accepted leakage level for ovens. That is roughly the same radiation exposure caused by automatic door sensors. The flashlight can sense movement including the faintest breathing. A commercial version of the device would cost nearly US $500 ( Business Week , October 13, 1997).