A density scanner consists of a bulky backpack connected to a large camera-like set of goggles. The user wears the goggles, which show the scene in front of him. The density scanner checks emissions from the electromagnetic spectrum and computes the density of the items observed. It can only give very general readings. The scanner is often used for locating hidden cables and wiring for repairs. The scanner does not really "see through" things. It only gives the density reading of the surfaces of things. The density scanner must be supplied with SEU to operate, and it uses 1 SEU for every 10 minutes of operation.