Upgrade The Existing Back Lock：Smart Deadbolt is installed on the inside of the door and perfectly fits over most single-cylinder deadbolts.it not only retains the function of the key to open the door for you, but also easily shares the lock access with your family members and visitors in App if you are not at home. Note: Compatible with smart devices using the same Tuya App/Smart Life App solution. Not compatible with TTLock App. AUTO-UNLOCK & AUTO-LOCK Smart Door Lock will automatically unlock as you approach the lock on your way to your home. REMOTE CONTROL With WiFi gateway(Sold Separately), makes your life smarter and more convenient. EASY INSTALLATION IN 10 MINUTES With just a screwdriver, you can upgrade your current rear lock to a Smart Lock in less than 10 minutes.