This is the part of the system that lets people know there is a professional alarm system installed. The site of a system installed by a professional company rather than a system bought at the local DIY chain may be enough to make the average burglar choose someone else to pray on. Our external sounders comprise of high volume siren generated by a twin piezo element unit, LED strobe, twin flashing lights to indicate the presense of a real alarm system, independent back up battery system to protect the sounder in the event of it being attacked.