Angelcare Movement MonitorThe Angelcare movement monitor AC300 is portable and can be used anywhere baby sleeps. The under-the-mattress sensor pad detects the slightest baby movements and alerts you if no movement is detected for 20 seconds. It is a great addition to the Movement Sensor with Sound Monitor from Angelcare if you have twins sleeping in different beds, in the same room. Can also be a great addition to the Angelcare sound monitor or any other sound monitor for that little extra reassurance