Expand your Ring Alarm system to secure each door and window in your home, and get alerts as soon as they open. Ring Alarm Contact Sensors easily mount to any door or window frame in your home for easy, DIY installation. Subscribe to Ring Protect, sold separately, to connect them to your Ring Alarm or Ring Alarm Pro Base Station and receive mobile alerts from the Ring App whenever your doors or windows open.1 You’ll always be the first to know when something’s ajar. Plus, if you’ve enrolled in professional monitoring3, you can choose to receive a call from the monitoring center when the Contact Sensor is triggered and request emergency assistance if needed.