GRAND MASTER KEYED PADLOCKS
Each padlock will open with the two keys supplied, and will also open with a master key and a grand master key. For example, 30 padlocks are ordered for the electrical department of a factory, 20 locks are ordered for the pipefitting department, and 12 locks are ordered for the maintenance department. Each employee is given a padlock with a pair of keys that only open his or her padlock. The electrical foreman has a master key that will open all 30 of the electricians' padlocks (but not the pipefitter or maintenance locks). The pipefitter foreman has a master key that will open all 20 of the pipefitters' locks (but not the  electrical or maintenance locks). The maintenance foreman has a master key that will open all of the maintenance padlocks (but not the electrical or pipefitter locks). The plant supervisor has a grand master key that will open all of the locks in the electrical, pipefitting and maintenance departments.