Nuki Smart Lock 3.0 Security Door WhiteDescriptionSpecificationsShipping The Nuki Smart Lock turns your smartphone into a smart key! Open your door with your smartphone instead of keys and simplify your everyday life. With Nuki you can assign virtual keys through the Nuki app to family and friends. Keys can be set to be used over a period of time, or indefinitely. Maintain a secure home by keeping track of who locked your door, when and whether its securely locked." For easy retrofitting