Characteristic:
1. No collision and no noise when slam the door.
2. Still could work under strong pressure on the door.
3. Sensor card to open the door.
4. Simple construction, low currency, low cost, less failure.
5. For both side of door, simple application.
6. Universal application, 3 times life-span than common electric lock allowed.

Characteristic (with sensor card):
1. No collision and no noise when slam the door.
2. Still could work under strong pressure on the door.
3. Easy connecting wires, two wire system, no positive and negative.
4. Simple construction, low currency, low cost, less failure.
5. For both side of door, simple application.
6. Universal application, 3 times life-span than common electric lock allowed