Add an extra level of protection to your home with Ring Alarm Home Security System Contact Sensors. Attach a sensor to any window or door within your home and immediately receive a notification when they open, even if you're at work. Sends instant alerts to your phone or tablet whenever a door or window is opened in your home. Monitor from your iOS or Android device. Attach the sensor to any door or window and connect it to the Ring Alarm Base Station (sold separately). Backed by the manufacturer’s 1-year limited warranty. Ring Alarm and all Ring Alarm accessories require a subscription for digital notifications, in-app features, digital arming/disarming, and integration with other Ring, Echo, and third party products. Subscription sold separately. Terms and conditions apply. Requires Ring Alarm Security Kit. Save up to $100 per year on home insurance with a professionally monitored Ring Alarm. (Actual savings vary depending on insurance carrier and policy).