The Union 2134E 80mm Keyed to Differ 5 Lever BS3621 Insurance Rated Deadlock Polished Brass is most commonly used to add extra security to external doors with a night latch or rim lock and has been tested to British Standard 3621:2004. The deadbolt is locked or unlocked by a key either side. It has a quality steel case (red enamelled) and solid brass deadbolt, finished with polished brass finish.   Other Variations The lock is also available as a keyed alike lock, with an 67mm case size (45mm backset) and with a satin chrome finish. Some of these variations can be found in th...