Patio Door Security Bar with Anti Lift Lock (White) Adjustable Shelves ) 0 Knob cross bore ) 0 Knob cross bore diameter (in Versatile smartphone compatibility Supports select Apple iOS and Android devices Wi Fi connectivity Use your home network to easily sync your doorbell to your smartphone or tablet Manage your doorbell with the Nest mobile app Receive alerts accept the live video feed and speak with your visitor all from your smartphone 24 7 streaming Check in anytime and view a 3 hour snapshot history to see what you missed HD talk and listen Hear visitors loud and clear with noise and echo cancellation Person motion and sound alerts Detect when someone may be waiting at your door even before they ring the doorbell Night vision Features 850 nm infrared LEDs Mounting kit included Requires a wired doorbell and chime Quick response Respond to visitors with convenient pre recorded messages even when you can't answer If the opening is less than 25 75 Product Width (in