what is deadlocking


The spring itself is not replaceable, you would need to replace the 19 centercase assembly.
The B250 Night Latch is a single cylinder deadlocking latchbolt where the latch is retracted by a key from the outside or by the inside thumbturn. Rotating the thumbturn and activating the hol...
If device backset is correct, replacing the device center case & center case cover with a F-24-R to add deadlocking to the latchbolt.  Parts to the F-24R center case & cover can b...
This configuration is not possible as the anti-pick plate of a "DL" or "F" device center case interferes with the LM/DM switch mounted also on the center case.