The Gimdow simply sticks to the inside of door, so you don’t need to change the existing lock. And due to it’s unique design, it can fit most American and European door locks.Because it is just a stick-on, you can quickly remove it in case of emergent situations. It has a wireless keypad on the outside, and an encrypted Bluetooth app to let you enter your property with a simple code or tap, but still with the original key. You can share temporary virtual key with people you trust, like your cat-sitter, family, friends or Airbnb guests. To make sure Gimdow keeps your house more secure, not less, we did not include WiFi, so the lock is not vulnerable to online criminals.