The Union 2134E 67mm Keyed to Differ 5 Lever BS3621 Insurance Rated Deadlock Satin Chrome 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 satin chrome finish.   Other Variations The lock is also available as a keyed alike lock, with an 80mm case size (57mm backset) and with a polished brass finish. Some of these variations can be found in the relat...