All of us like returning home after a day’s work to be in a clean and comfortable porch of his home and at the same time without feeling a sense of anxiety and excitement for their own safety to reach his apartment. That’s why lately there are more people who care about the fate of the native porch. These people are trying to protect it from various hooligans fans to drink alcohol in the stairwell, vagabonds, thieves and robbers – the installation of a solid iron door, but … unfortunately with a combination lock. Suppose the situation: locked closed for regular key, which is available in each apartment, and you are expecting guests, a doctor or a plumber, but live on the top floor. And every time you have to go down to open the door. Is it comfortable? Of course – no! And here’s another story: if your entrance with an ordinary combination lock, the one hundred percent sooner or later frequently used buttons on this castle just overwritten, so you can easily find out the code from this castle. How do you avoid all of this and at the same time make your life more comfortable?