Key Features . Keyless digital door lockSuitable for every doorPatented Duracore™ cylinderCompatible with iOS and; AndroidUp to 2 year battery lifeSKG *** Quality mark The Bold Smart Cylinder SX is certified by SKG with 3 stars. This gives the product the most stringent burglar-resistant classification. Because the Bold Smart Cylinder can also be used in combination with anti-core pulling fittings you don\'t give burglars a chance. Suitable for The Bold fits all doors with an inner size of up to 35 mm. The outer size can be extended to 45 mm with the supplied extension pieces. The distance from the center of the cylinder to the inside of the door to the door jamb must not be less than 30 mm. 2 Year Battery Life The Bold Smart Cylinder is simple to install and requires no wiring. By applying new techniques with low power consumption the battery will last for at least 2 years. Even with intensive use of 25 activations per day. The lifespan is therefore many times longer than with motorized smart locks. Two-Factor Authentication We use a number of state-of-the-art solutions to guarantee the highest safety of our product. We make sure that our product remains easy to use. Both your phone number and your email are verified separately but in a simple way. For example the chance that someone else can register in your name is nil. End-to-End Encryption All communication between the lock and the Bold servers is encrypted in the same way as the most recent online banking software. For example the Bold Smart Cylinder is not vulnerable to eavesdropping on the wireless signals hacking the smartphone or other manipulation of communication. Backup PIN The Bold Smart Cylinder is completely keyless even if you forget your smartphone once or if its battery is empty. In that case you can always open the door with a backup pin code. You generate this code yourself in the Bold app and enter it by turning the outside knob. What\'s in the Box . 1x BOLD Smart Euro Profile Knob Cylinder1x Battery3x Length Adapters OutsideInstallation Tools. .