Outdoor Contact Sensor For Ring Alarm. Help secure outdoor gates, sheds, guesthouses, and windows with Ring Alarm Outdoor Contact Sensor. Get mobile alerts when your outdoor gate opens, or set the sensor to automatically trigger your Ring Alarm siren when armed in Home or Away mode. With its weather-resistant design, the Ring Alarm Outdoor Contact Sensor can withstand outdoor use in most climates. Outdoor Contact Sensor comes with mounting tape and screws for easy installation on most surfaces. Requires Ring Alarm or Ring Alarm Pro. Ring Alarm and the professional monitoring service are available and ship only within the U.S. (excluding territories) and Canada. If you?ve enrolled in Professional Monitoring, you can choose to receive a call from the monitoring center when the Outdoor Contact Sensor is triggered and request emergency assistance if needed.