Chubb Dual Control
Control Safe Lock Dual Control Lock Lock
by Chubb London C 1929 7 Lever. 4 x 4 1/2" Body Case.
key is inserted in the lock and its function is to set the gatings
in position for the second key to throw the bolt. The lock cannot
be opened by the use of the second key only. The first key is
again required to set the gatings.