Are you worried about exposing your PIN while you unlock your phone? Here comes Knock Lock - Applock for the rescue. The innovative Lock Screen that will leave intruders baffled! Knock Lock Screen - Applock is the new way of locking devices. All you need to do is tap Knock Knock on the screen and unlock your device. MAGIC! No one able to guess what you did to open your lock screen because its fully INVISIBLE. Available Lock Type 1. Knock Lock 2. Pattern Lock 3. Time password lock Features