Frame version, self-locking, continuous handle nut for interchangeable fittings. High burglary protection - The front door is always locked, day and night. This means protection against burglars and other unwanted guests. If necessary, the door can be kept open via a key switch. Safe escape route - Despite permanent locking, the house can always be exited through the front door, in case of danger and during normal operation. The issue of escape route security is solved once and for all. Great comfort - The locked front door can be conveniently opened from inside the apartment. If the door closes again, it is automatically locked.