1. No Drilling, indoor installation,concealed installation and no marks outdoors. 2. Outdoor card swiping unlocking, mobile app unlocking. Indoor one click unlocking, manual knob unlocking. 3. The door automatically locks when closed. 4. live voice broadcasts. 5. normally open function(passage mode / toggle mode) and low voltage alarm function. APP version unlock record monitoring: IC card and APP unlock records are . After operating the lock on any mobile app, connecting to , and synchronizing information, all unlock records can be seen on the administrator app. application:Door locks for indoor non-metallic doors such as homes and offices. Door thickness not exceeding 60MM Colour:Black Material:plastic+metal Package Contents: 2 x Smart Door Lock Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.