A padlock includes a shell, a shackle, a limit knob, an indicator and a lock core. The shell includes an opening in a wall thereof. The shackle includes a long section movably inserted in the shell, and a short section extended from the long section and located out of the shell. The limit knob is partly received in the shell via the opening and includes a button located out of the shell. The indicator is disposed on the limit knob and capable of moving to a predetermined position which is out of the shell. The lock core includes a rotor configured to be driven by a key so as to move the limit knob to a first position where the button of the limit knob keeps the shackle from rotating and a second position where the button of the limit knob allows the shackle to rotate.

A security apparatus for securing a portable electronic device to an immovable object includes a locking head having a base and a plurality of engagement portions extending from the base. The plurality of engagement portions is configured to be inserted into an aperture of the portable electronic device. The locking head also includes a linear portion positioned between the plurality of engagement portions and extending from the base. The linear portion is twistable about its length to move the plurality of engagement portions radially outward. The security apparatus further includes a security device attached to the locking head and configured to engage the immovable object.

Method of making airline luggage inspection secure while accommodating the needs of the traveler comprises making a special lock available to airline travelers, the special lock having a combination lock portion and a master key lock, the master key lock portion receiving a master key that can open the master key lock portion of any special lock of this type. The special lock is designed to be applied to an individual piece of airline luggage and has indicia conveying to luggage purchasers that the special lock is approved by a luggage screening authority and conveying to the luggage screening authority that the special lock can be opened using the master key. The method includes providing the luggage screening authority directly or indirectly with exclusive access to the master key. The manufacturers and/or providers of the master key and special lock retain copies of the master key.

A portable lock includes a wireless signal receiver. The lock may be unlocked by transmitting a wireless unlock signal from a portable device such as a cellular telephone. Various actuation mechanisms which may include a solenoid, motor or memory wire of a type that contracts when energized are provided in example embodiments. Self-locking embodiments are readily operated with one hand.

A lock includes a locking body, a non-locking body, and at least two shackles each independently removable from both the locking and non-locking body.

A portable lock includes a wireless signal receiver. The lock may be unlocked by transmitting a wireless unlock signal from a portable device such as a cellular telephone. Various actuation mechanisms which may include a solenoid, motor or memory wire of a type that contracts when energized are provided in example embodiments. Self-locking embodiments are readily operated with one hand.