I've seen Yale mortise cylinders in use that hold two cores- one for normal operation and one for a master key. Does anyone know what these are properly called? I think they may be a good solution for a building I'm working on, but without knowing the proper terminology I haven't been able to find much information. Links to distributors would be especially appreciated, though I can go look for myself once I know what I'm looking for.
thanks!
 |
|
||||||||||||||
 |
|
 |
|
|
|
