The door is automatically locked when it's closed so it prevent the user to leave the door open accidently. If the dead bolt is not normally closed or open, it try two times again and then it aleart with alarming sound.
The Voice and Alarming sounds help users to use the door lock easily.
If the batteries of door lock are in low voltage, the door lock alerts users with alarm sound and blink red LED for instant battery change.
It could be used at night by muting the sound of lock not to disturb residence or other family members.