The mechanical lock itself installs very easily. I found some difficulty with the setup and app control. When installing, note per instructions the handle needs to me aligned properly for the lock to function. Also, connecting the power clip to the control board took a few tries before finally connecting. The default language in manual setup is in Chinese and the best way to change is through the downloaded app, unless you can understand the language. Instructions that were included were a bit unclear with some confusion. Had to play around in the app to understand many of the features. For some features, additional charges were required in the app. These were to allow phone and/or text alarm notification services. They were considerable more than what I paid for the lock itself. App registration requires an email and other permissions for Bluetooth, location and notification allowances to activate basic features. Other features included in the app allow the sync with Alexa and Google Assistant. All in all, the lock functions well when set up. It allows the issuing of multiple codes for users from 6 to 10 digits. It also allows administrative codes for the lock setup and to enable user features. Temporary codes can be created with time limits imposed. Logs are created to check when and who activated the lock. When installed , the outside handle remains in an auto lock state to keep the door secure until code is entered. The inside handle is normal and opens the door as needed. The lock responds well when using the cell phone app with just a swipe of the app screen. As a backup, keys are included to override the code entry or if the batteries abruptly dies. I bought two of these locks for my house and both sets of keys were not inter-changeable. Each set was different. I am happy with the purchase and the price paid.