Internal speakers & sounders - some with strobe lights

A  speaker is usually fitted so the user of the alarm can hear the entry and exit tones throughout the entry exit route and from immediately outside the final door.  This reminds them to unset their alarm, and also confirms the system has successfully set.  Speakers can also activate when the external siren operates to give those inside the building notification that their alarm has activated.  Internal sounders are also available (sound bombs), they make a noise internally when the alarm activates. They are different from the speaker because they make no sound during the setting and unsetting routine.  Internal sounders with strobe lights built in are also available.