Abstract: A lock includes a lock sleeve, a lock body is disposed in the lock sleeve in a free rotating manner, a lock assembly, an actuating member, and an actuation key. The lock body includes a lock rotor coaxially and rotatably disposed within the lock sleeve, and a lock core coaxially and rotatably disposed within the lock rotor and defined a keyway at the lock core. The lock assembly normally locks the lock core with the lock rotor in such a manner that the lock body is free to rotate within the lock sleeve. The actuation key is slidably inserted into the keyway of the lock core to unlock the key lock unit, wherein when the lock assembly is unlocked by the actuation key, the lock core is rotated within the lock rotor to drive the actuating member to rotate and to longitudinally move for actuating a latch assembly.