• Kidde Battery Operated 4” Smoke Alarm

Kidde Battery Operated 4” Smoke Alarm

The Kidde Fire Sentry Battery Operated 4" Smoke Alarm i9040 is a battery-operated smoke alarm that utilizes ionization sensing technology. The four (4) inch unit is smaller in diameter giving it a discreet design with the same quality you would expect in a Kidde manufactured product. The i9040 is powered by a 9V battery, providing continuous protection, even during power outages. This easy-to-install unit includes a test button to verify the detection electronics are working as intended.

This alarm uses ionization sensing technology. Ionization sensing alarms may detect invisible fire particles (associated with flaming fires) sooner than photoelectric alarms. Photoelectric sensing alarms may detect visible particles (associated with smoldering fires) sooner than ionization alarms. Kidde strongly recommends that both ionization and photoelectric smoke alarms be installed to help insure maximum detection of the various types of fire that can occur within the home.


  • Battery operated, 9V battery included
  • Test button
  • Low battery indicator chirps to alert user to change the battery
  • Discreet design


  • Power source of 9V battery (included)
  • Audio alarm of 85dB at 10 feet
  • Ionization sensor
  • 4" diameter x 1.45" depth
  • 3-year limited warranty from Kidde