Covert Security Cameras are designed to be hidden or inconspicuous, and can be housed in an almost unlimited number of objects. In some cases they are referred to as Spy Cams, or Nanny Cams. Common devices such as PIR Motion Sensors or Smoke Alarms are often used for hidden cameras. Covert Security Cameras are popular as add on cameras to supplement a system and are used in both residential and commercial surveillance applications. There are a variety of Covert Style Cameras including Hard Wired, Wireless or Wifi, Self Contained DVR Covert Cameras and Wearable Hidden Cameras.