One of the most important points responsible for work of a lock is placed on the inner side of a dead-bolt (bar) in the place of a stand fixing. This stand fixes the levers, when the stand is broken the lever mechanism falls to pieces and can't hold the dead-bolt in a closed position. The stand is placed inside a lock case, that is why burglars have to reach it from the outer side of the door by means of drilling out several obstacles: door leaf, armour plate or armoured case cover, lock case. The armour plate and armoured case cover serve for protection of the inside lock mechanism against drilling.

The advantage of BORDER armoured covers in comparison with ordinary ones consists in the following: first, they are of increased strength, we use manganese steel Ц85, like in flak jackets, the steel stands a Kalashnikov gun shot; second, we fix the armoured cover with reinforced screws in 4 points.

More often armour plates are fixed with small screws (e.g. M3), it is not reliable enough. Though it does not influence burglary-resistance during drilling, some burglars-professionals "knock down" such a plate through a keyhole. To exclude this possibility the BORDER armoured cover is fixed to the lock case with M5 screws in 4 points. It is impossible to knock down the cover with this kind of fixing, and the steel with thickness of 4,6 mm becomes a serious obstacle during an attempt to drill out a secret mechanism or to widen a keyhole for inserting a "svertysh".