A warded lock (also called a ward lock) is a type of lock that uses a set of obstructions, or wards, to prevent the lock from opening unless the correct key is inserted. The correct key has notches or slots corresponding to the obstructions in the lock, allowing it to rotate freely inside the lock. Large warded locks are still in use today in the UK and Ireland for internal and external doors. Warded locks in America are commonly used in inexpensive padlocks, cabinet locks, and other low-security applications, since a well-designed skeleton key can successfully open a wide variety of warded locks.