This refers to locks that are installed on the surface of a door rather than inside the door (see cylindrical locks and mortise locks). They are fairly easy to spot, because the lock consists of a box bolted onto the inside of the door.Safe penetration
This becomes necessary when a safe is locked shut and cannot be opened by the ordinary means: the combination or key is lost, or the safe lock has been vandalized or has simply failed. This can mean minutes and no damage if it is a cheap lock-box purchased from a discount store. It can mean hours or days of technicians using noisy drills and fancy equipment if it is a well-constructed safe or a vault door. This is a specialized service that not all locksmiths offer.Single-motion egress
This is a feature that some fire inspectors require on some doors. (Fire codes are still largely a local matter, though standardization is becoming the trend.) This means that a user must make only one motion in order to open a door to exit. For example, a door which is designated for single motion egress cannot have both a latching doorknob and a separate deadbolt, since that requires the user to perform two distinct actions to open the door. There are products designed for properly securing doors that require single-motion egress. A professional locksmith can make sure you comply with local codes while still protecting your property!Skeleton key
This is a generic term that refers collectively to the keys that operate antique or antique-style furniture (see barrel keys) and antique or antique-style door locks (see bit keys). It is simply not true that there is one skeleton key that works all locks.Strike
This term refers to a metal plate, either curved or flat, that is installed on the door frame opposite a door lock. The latch or bolt of the lockset actually protrudes into the strike when the door is closed and/or locked. The proper installation and adjustment of the strike is critical for the secure and reliable operation of the lock. In short, the strike is the other half of the lock! Strike adjustment is one of the most common repairs that locksmiths make.