With these concealed single-casing lead covers you can securely lead the cable from the frame into the leaf. Thanks to the covert design and installation on the frame side, the cable is inaccessible when the door is closed, so it is sabotage protected.
Single-casing version.

Since the wire runs through a metal spiral hose, any cable damage due to rupture or clamping is out of the question.
For wooden, metal and palstic doors.