The Red Shield WS-100 is an independent, plug and play alarm system. The set is very complete, consisting of a base station, motion detector, 2 window/door sensors, and a remote control. You can link all elements together via the 868 frequency. When the system detects something, a loud siren with a 120-decibel audio signal will be set off. That's louder than average, so all your neighbors will know something is wrong in your home straight away. You can expand the alarm system with even more motion detectors, so you'll know when there's an intruder entering your home. You need 2 9V and 4 AAA batteries to get the system to work straight away. They're not included by default, so that's something to keep in mind.