OnGuards Alarm Lock comes with high security locking mechanisms which secure both sides of the shackle. The 14-16mm shackles are hardened steel making them impervious to prying, jacking or cutting. The round profile gives the lock smooth edges, elimninating any leverage points. The shackles are fully coated, ensuring they don't damage the finish or paint job of whatevcer you're locking it to. The Auto Arm /Disarm Alarm comes with shock and movement sensors which set off a 120db alarm, alertingeveryone to any would be attackers.