This tools is self explanatory. Although the likelihood that you are being monitored through your webcam is low, there are no way of knowing 100%. It is fairly easy to connect to it remotely when you have access to a computer. So why run the risk?
These are great and works on both your computer, monitors with webcam, and on your phone. They are very thin so there is no problem shutting the laptop completely.
I like the packs with 3, but you can buy in different packages. Give one to your loved ones, or invest for the office.
Read more about it here, and get yours.