A hand-held Doppler radar device that is able to see through walls of buildings. Users of the device simply hold it against a wall and then push a button to send radar pulses through the wall to detect if anyone is inside. It works by picking up human breathing and movement within the building. The device covers a conical view of 160 degrees and has a range of around 50 feet.

The Range-R can penetrate most common building wall, ceiling or floor types – including poured concrete, concrete block, brick, wood, stucco glass, adobe, dirt, but it does not work through metal. Moreover, if a wall is saturated with water, it also may reduce the device's effectiveness.

The device has caused much privacy concerns as there is little to stop any member of law enforcement from placing one against anyone's wall just to see if they're home. In 2013, the Supreme Court heard the case of Florida vs Jardines. In the case, police led a drug-sniffer dog to a suspect's porch. The dog detected marijuana plants. The suspect was arrested. The court suppressed that evidence. Citing the Fourth Amendment, the court argued for "the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion." It added that the area immediately surrounding the home is part of the home itself for Fourth Amendment purposes.