Putting together the serial lock, the big brass padlock that is used on street collection boxes and vehicles, is the ... There are 70 possible tumbler combinations for a serial lock. ... There are more than 100, 000 different lock box key codes.
|Author||:||United States Postal Service. Dept. of Public and Employee Communications, United States. Post Office Dept. Office of Public Information, United States Postal Service. Communications Dept|