The security lock mechanism 309X is used primarily where an insurance-related locking of the door must be ensured by a 20 mm bolt projection, Self-locking with cross latch and bolt, Mechanical sequence control between cross latch and control latch, Integrated panic function via the inside handle, Change function for unlocking with a key from the outside, Suitable for installation in fire doors, SI-LOCK MECHANIC 309X501, 55/20/72 PZ DIN LEFT