A121 Alarm Horn Sounder

The A121 is a very high output 124dB(A) automatically synchronised alarm horn sounder. Globally approved for fire, marine and general signalling applications. Featuring 64 alarm tones and 4 remotely activated stages.

Low current consumption and high SPL in a outdoor rated enclosure ensure the A121 is suitable for all applications including fire, security and process control. Designed to withstand the harshest of environments. Constructed from lightweight, impact and fire-resistant ABS, the A121 employs the latest in reliable D Class amplifier technology for superior sound output with low current consumption. The A121 is a member of the versatile AlertAlarm family of industrial alarm horn sounders – also available with Xenon, AL121X or LED beacons, AL121H. SIL1 & SIL2 Route 2H compliant to IEC61508 (2010) as standard.

Product code: A121


Main features and benefits:

  • Automatic synchronisation
  • Continuously rated
  • Dual M20 or 1/2″NPT clearance cable entries
  • Duplicate pluggable cable terminations – Class A
  • Ingress protection IP66 Type 4/4X/13/3R
  • Conformal coated (tropicalised) electronics
  • 64 alarm tone frequencies and 4 remotely activated alarm stages
  • Available with custom tone configurations and frequencies
  • Diode polarized for use in supervised circuits


  • UL: UL464
  • cUL: CSA C22.2 No 205-17
  • ULC: CAN/ULC-S525
  • UL EU: (EN54-3) UL-EU-01153-CPR
  • CPR 305/2011: 2821-CPR-0108
  • MED 2020/1170: MEDB000074G
  • DNV GL-CG-0339: TAA00002ZU
  • USCG COA 161-002-68-0
  • EAC CU TR 043/2017: B.00291/21
  • EAC: RU D-GB.GA05.B.12595-20
  • RMRS Marine: No. 19.00193.278
  • SIL1 & SIL2 compliant to IEC61508 (2010)
  • CE, UKCA

Click on the links below to download the following attachments:

Marine Fire Detection Catalog (page40-47) .pdf

A121 Data Sheet.pdf