AKA covert or spy cameras, hidden security cameras are used for stealthy video surveillance at home in most cases. These devices can be built in the guise of common household items such as smoke detectors, clocks, sunglasses, and baseball caps. Household items are rarely suspected of housing a video recording device. If there is a babysitter or maid that comes and goes in your home and you feel you need to check up on them from time to time, then consider a wireless hidden security camera.
Businesses also sometimes use wireless hidden security cameras to see what is going on with employees, but be careful before putting a microphone along with the camera; some states require by law that everyone being recorded must consent.