fitted with a security system consisting of a motion detector and panel inside the container. The panel can trigger a siren, strobe, or light to deter intruders, or use a radio signal to alert security guards. Items that were packed incorrectly may come loose and cause a false response from an inside motion detector. If criminals break in by cutting through a wall of the container, the obstructed motion detector becomes useless. Tomographic motion detectors work well in intermodal containers because they do not require a line of sight to detect motion. The entire container is covered by a volumetric sensing mesh that is not blocked by equipment or inventory. Tomographic motion detection is not prone to misdetection due to dirt buildup as is the case for beams and infrared sensors. Non-shipping uses[edit] Containerized equipment[edit] File:Hammelmann Diesel unit – built into container Container-sized units are also often used for moving large pieces of equipment to temporary sites. Specialised containers are particularly attractive to militaries already using containerisation to move much of their freight around. Shipment of specialized equipment in this way simplifies logistics and may prevent identification of high value equipment by enemies. Such systems may include command and control facilities, mobile operating theatres[82] or even missile launchers[83] (such as the Russian 3M-54 Klub surface-to-surface missile). Complete water treatment systems can be installed in containers and shipped around the world.[84] Electric generators can be permanently installed in containers to be used for portable power.[85] Repurposing[edit] Container City in Cholula, Mexico uses fifty old sea containers for 4,500 m2 (48,000 sq ft) of workshops, restaurants, galleries, etc., as well as some homes. Containers have long been used for other purposes, typically but not always at the end of their voyaging lives. US military often used their Conex containers a