... the lock adopts two steps to operate,alarm or without alarm. alarm lock,motorcycle lock set,siren lock desprition:1 ... “DU”, which means it is coming into the alarm situation,after 15 seconds , when the lock or ... it will give an alarm and keep alarm with serial movement or viberation. Each alarm will last for 10 seconds ... later on ,please keep this usage direction.. alarm lock,motor lock,siren lock