Having a security camera monitoring your home or office will help you know what is going on, even when you are not present.
One of the best cameras you can get is this covert HIDDEN Smoke Detector Camera 3.6mm with AUDIO.
This is a Hybrid AHD/TVI/CVI/CVBS 720p 4 in 1 solution Smoke Detector Camera 3.6mm with AUDIO, disguised within a smoke detector shell, insuring that no one will know that you have a hidden camera monitoring their activities.
Plus, having the audio included within the device is a feature that many other security cameras do not offer. This device uses a 3.6mm lens.