December 2, 2008: There is another player in the market for "see through walls" devices. Two years after the first of these systems, RadarVision, became available, we now have the Xaver 400. This one weighs 6.5 pounds, and can see through non-metal walls at a range of up to 20 meters (63 feet). The battery lasts 2.5 hours and the device can broadcast images, up to a hundred meters, to another display.

The original RadarVision showed up in Iraq in 2006. This was particularly welcome, as urban warfare is particularly difficult because, once inside a building, you have to deal with all those walls. Well, just like electronics came up with a solution to night fighting (night vision goggles), a similar device has been developed for literally seeing through walls. Well, at least most walls. The nine pound RadarVision can't see through metal walls, but will give you an image of anyone behind any other wall material, including up to a foot of brick, concrete or stone. It can also see through multiple walls. Using a 90 minute battery pack, the image is particularly good if someone in there is moving. RadarVision was also incorporated in some combat robots. Such a droid can check out a building more quickly by using its RadarVision to see through walls while moving down a hallway. Many Iraqis have long believed that American troops had devices that could see through walls. There's no telling what the appearance of devices, that do just that, will have.

There is now a RadarVision 2, which has similar capabilities as Xaver 400. Both of these devices sell for between $20,000-$30,000. Police departments buy a lot of these, as well as military organizations that can afford to provide their infantry with high-priced gear.