Electronic coded lock on a door
Coded Door Lock: Mechanical and Electronic : Electronic Coded Lock On A Door
Quote from Article entitled Coded Door Lock: Mechanical and Electronic:
A feature of mechanical coded locks is that they do not have a keyhole which guarantees its high reliability and reduces probability of housebreaking. With the help of a certain coding of cylinders or rollers in a lock, you can set up the key code by own forces or change the factory settings. You can install a mechanical coded lock on any door - metal, plastic or wood. It is easy to install a coded lock on a front door by own forces. It is desirable that the thickness of a door leaf is at least 3 cm.
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