Message to Our Customers

First Alert

Model # SA305CN3

Internet # 202433884

Battery Operated 10-Year Lithium Smoke Alarm

This item has been discontinued.
The Home Depot no longer carries this specific product.

$14.97 / each


Model # SA305CN3

Internet # 202433884

First Alert smoke alarm with long-life lithium battery. Long life lithium battery reduces costly battery replacement and frequent maintenance. Mute feature silences nuisance alarms. Single button tests detector functions. Easy access front loading battery door: no need to remove alarm from ceiling to change battery. Ideal for Hallways, Bedrooms and Living areas especially in hard to reach locations. 10-year limited warranty. Meets UL standards.

  • 9-Volt removable 10-year lithium battery
  • Mute button
  • EZ access battery door
  • Optional theft-prevention lock to secure the detector
  • Ionization smoke sensor
  • Long life lithium battery included
  • Loud 85 dB alarm
  • 10-year limited warranty
  • Meets UL217 standard
  • America's most trusted brand in home safety

Info & Guides

You will need Adobe® Acrobat® Reader to view PDF documents. Download a free copy from the Adobe Web site.


Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Alarm Sensor Type 
Alarm Type 
Alarm/Detector Features 
10-Year Battery 
Commercial / Residential 
Commercial / Residential 
Connector/Contact Type 
Power Source 
Voltage (volts) 
Warranty / Certifications
Certifications and Listings 
1-UL Listed 


Rated 4.2 out of 5 by 6 reviewers.
Rated 5.0 out of 5.0 by first alert smoke alarm alarm was a great price first alert is a good name in security products the one I replaced was a first alert it was long over due for replacement March 10, 2015
Rated 2.0 out of 5.0 by Bought three, one works I chose this smoke alarm because I have been happy with my three electrician installed ones. I bought three more for the rest of the house but only one of them works. There is something wrong with the battery doors which make it difficult to install the battery. Once the battery is finally in place the test alarm does not engage. I am returning the defective ones and regretfully looking at other brands. February 3, 2015
Rated 5.0 out of 5.0 by set it up and forget it. replaceable 10 year battery. lithium 9 volt style. just need to test once a year. we test twice a year on the time change dates. we just replaced the previous model with this one. it lasted 15 years with now working problems wanted the same thing. been in place now for 60 days with no issues. easy to install right in the place of the previous 10 year version. March 12, 2013
Rated 5.0 out of 5.0 by Home daycare Approved! Great product! Affordable with the 10yr litium battery needed to meet State Fire Marsall requirements for my home day care. I bought four of them which earned me free shipping even better! Would highly reccomend! August 10, 2014
Rated 5.0 out of 5.0 by Everything was as I had hoped Nice that the mountain ring is the same as the old units being replaced. Made for VERY EASY installation October 15, 2013
Rated 3.0 out of 5.0 by The detectors are easy to hear. The instructions made installation go smoothly. I would recommend them and buy them again. April 9, 2013
  • 2015-05-28T10:33:12.086-05:00
  • bvseo_lps, prod_bvrr, vn_prr_5.6
  • cp-1, bvpage1
  • co_hasreviews, tv_6, tr_6
  • loc_en_US, sid_202433884, prod, sort_default
1-6 of 6


Standard Shipping includes delivery by small parcel service. Processing time varies by product.

If product is eligible for shipping to AK, HI and US Territories additional transit time and remote surcharges may apply.