Knox Box

A Knox Box, known officially as the KNOX-BOX Rapid Entry System is a small, wall-mounted safe that holds building keys for firefighters to retrieve in emergencies. Building managers may obtain a Knox Box, which the local fire company can open, and permanently mount it near the entrance to their building, placing a copy of the building's keys inside. Knox Boxes are an alternative to leaving keys on deposit at the local fire department where they might become obsolete or be misplaced at the time of a fire. In a district with extensive Knox Box use, firefighters need only carry the master key to the Knox Boxes in the area, instead of keys to individual buildings.

Advantages
Knox Boxes simplify key control for local fire departments. They also cut fire losses for building owners since firemen can enter buildings without breaking doors or windows.

Disadvantages
The disadvantage of the system is that it provides a single point of failure for security. If the key to a district's Knox Boxes is stolen or copied, a thief can enter any building that has a Knox Box. Some building managers wire Knox Boxes into their burglar alarm systems so that opening the box trips the alarm, negating their use in facilitating clandestine entry.