An extremely strong container, usually made of metal and sometimes built into a wall or vault, designed to protect money or other valuables. A bank safe is fireproof, strongly built, and equipped with a well-locked door. A furrier's safe provides, in addition, cooling, ventilation, and protection against insects. A safe or vault is a complete structure, the walls, floor, and ceiling being as much a part of the protective features as the more conspicuous door. For utmost protection, a vault is so large and heavy that it cannot be removed. Combination locks eliminate the keyhole as a weakness, and eliminate the key, which could be stolen or duplicated. A time clock built into the locking mechanism unlocks the vault entirely from the inside. The time lock operates only after the elapsed time, set when the vault was closed. Walk-in vaults are furnished with shelves, locked drawers, and cabinets for systematic and compact storage of valuables. The vault may be air conditioned and may have a telephone extension inside.