This second generation of the Ring Alarm Motion Detector is an expansion for your Ring Alarm. The sensor is smaller than the old one and it's easy to mount. It also won't respond to your pets. You mount the motion detector on a flat wall or in the corner of a room. You'll get a notification via the alarm if the sensor detects movement. Choose for yourself if the alarm sets of an audio signal in your home, or if you just get a notification on your smartphone. To use this expansion, you always need a Ring base station. The alarm only goes off if it's been turned on via the control panel.