Ring's Alarm system offers whole-home security in an easy to set up DIY package. Using the Ring app on your smart device (available on i OS & Android) you can can get notifications when someone enters a room, opens a window, or sets off the siren. You can change Alarm modes via the app, & if you should forget to set it before you leave, you can set it remotely from your smart phone. Expandable, & working with Ring's range of video doorbells & security cameras, Ring products allow you to set up an integrated ring of security around your home for peace of mind. Ring Alarm Contact Sensor The Alarm Contact Sensor connects to the Alarm Base Station & mounts to any door or window frame in the home. You can choose to get audio or mobile notifications whenever the doors or windows open. They can trigger your Alarm if someone tampers with the Contact Sensor & the system is armed in Away or Home Mode. Please note: This add-on component requires the Ring Alarm Base Station in order to work, which is available as part of the Ring Alarm Security System (sold separately).