The DEFCON MKL Cable Lock includes 25 sturdy locking devices featuring a 6 foot steel cable with a pass through loop on one end and lock on the other end. Any attempts to remove one of the individual locks, will noticeably damage the computer, preventing resale and therefore discouraging theft. The locks utilize the security slot already built into your laptop computer. Each individual Key Lock also ships with two identical keys, giving you the peace of mind of a back-up key. The keys are different between each of the 25 included locks. Two Master Keys are shipped with each 25 pack.