Alarm function combines locking function with alarming function. Built-in movement triggered alarm, which can emit loud sound when the lock is hit or shaken.Adopts MCU core procedures, high-tech integrated circuit and digital sensor chip.Can be set to two states: mechanical lock and alarm. Extra batteriesEach lock is pre-fitted with 6 LR44 batteries. You will also get a pack of batteries FREE (12 battery pack). This lock can be used as an Ordinary. Alarmed by simply taking out the shackle and inserting it back into the lock the other way round .When the lock is Alarmed a single Bleep will be heard. Once armed it has a unique program that controls the sensitivity, this is very important, as you don't want it going off all the time when its windy, our locks are designed with a unique microchip that controls the sensitivity, There are similar looking products on the market but none that have this technology built in. The lock has three sensitivity levels LOW-MED-HIGH.When it is in alarm mode, if there is any slight wind movement the alarm will not sound, the control unit can recognize tampering and innocent movement i.e. wind conditions, if tampered with, the lock will sound 3 ear piercing bleeps and automatically increase sensitivity if tampered again within 1-30 seconds just even a slight movement or any foreign metal contact on the shackle will immediately sound a 10-second 110db alarm. After the 10-second alarm has sounded the lock will be in a high alert state (maximum sensitivity) for 30 seconds and will repeat the 10-second alarm if tampered with again and thereafter will drop sensitivity one level at a time after it has sensed no movement for 30 seconds. This unique technology ensures no false alarms.lock designation. The lock is designed for many applications.What you are purchasing is a portable alarm that has built-in movement sensors, whatever you attach it to. If the item is moved or tampered the alarm will sound.