First Alert 10-Year Battery Combination Smoke & Carbon Monoxide Alarm | SMCO210 Slim Profile Design, Sealed Battery

By First Alert

9.8Excellent matchFeature and use-case score

Combines smoke and carbon monoxide detection with a sealed 10-year lithium battery, in a slim profile First Alert states is about half the depth of a standard alarm.

Combined electrochemical CO sensor and photoelectric smoke sensor
Sealed 10-year lithium battery with end-of-life warning
Slim profile roughly half the depth of a standard alarm

See Price at the store →Price, delivery, and configuration can change at the retailer.

ByTopFiveFind Research Desk

How this was made: AI-assisted research and drafting organize the evidence. Exact product identity, source claims, owner-feedback patterns, conflicts, and publication checks are documented before indexing. No hands-on or human-expert testing is claimed unless a page explicitly shows that evidence. Read the full methodology.

Best fitBest Overall (Combo Smoke + CO, No Battery Maintenance)

CategoryVacuum Sealers

BrandFirst Alert

Catalog score9.8 / 10

Product overview

First Alert SMCO210: What to Know

Per First Alert's own product page, the SMCO210 pairs an electrochemical CO sensor with a photoelectric smoke sensor in one unit, sold under the company's "Precision Detection" branding, which First Alert states is built to comply with newer industry standards aimed at reducing nuisance alarms triggered by cooking. The sealed 10-year lithium battery means no periodic battery swaps or low-battery chirps for the alarm's rated service life, after which First Alert states an end-of-life warning signals it's time to replace the whole unit.

First Alert's spec sheet lists an 85 decibel sound output at 10 feet, UL 217 and UL 2034 compliance (the relevant safety standards for smoke and CO alarms respectively), and a slim physical profile measuring roughly 5.68 x 1.3 x 5.68 inches — noticeably thinner than a typical puck-shaped alarm, which the company positions as a lower-profile ceiling appearance.

This is a battery-only (non-hardwired) unit per First Alert's listing, which makes installation straightforward without any electrical wiring, but means it doesn't tie into your home's power or interconnect with hardwired alarm systems the way some combo units do.

Key Listed Features

Combined electrochemical CO sensor and photoelectric smoke sensor

Sealed 10-year lithium battery with end-of-life warning

Slim profile roughly half the depth of a standard alarm

UL 217 and UL 2034 compliant, 85dB alarm at 10 feet

Good fit for

Best for buyers who want one unit covering both smoke and CO without ever replacing a battery for a decade
Good if a slim, lower-profile ceiling appearance matters to you over a bulkier standard alarm
Not a fit if you specifically need a hardwired unit that interconnects with existing house wiring

Check before buying

ASIN B0CJMMVST2 corresponds to the single-unit SMCO210 — First Alert sells a voice-alert version (SMCO210V) and multi-packs under separate ASINs
Specifications (sealed 10-year battery, dual sensor types, UL 217/UL 2034 compliance) verified against First Alert's own official product page rather than only the Amazon listing text
Amazon's live page for this ASIN returned an automated bot-check screen during our research, and the Internet Archive was offline at the time, so no cached snapshot was available to confirm a live star rating or review count

Research sources

Buying questions

Quick Answers

What happens when the sealed 10-year battery runs low?

Per First Alert's own materials, the unit includes an end-of-life warning that signals when the sealed battery (and the alarm itself, since the battery isn't separately replaceable) needs to be replaced. There's no periodic battery-swap maintenance during the alarm's rated service life.

Is this the same as the SMCO210V?

No — per First Alert's product lineup, the SMCO210V adds voice alerts that announce the type and location of the hazard, while the base SMCO210 described here uses a standard alarm tone without voice location announcements.

First Alert 10-Year Battery Combination Smoke & Carbon Monoxide Alarm | SMCO210 Slim Profile Design, Sealed Battery

First Alert SMCO210: What to Know

Key Listed Features

Quick Answers

Similar Products

First Alert Battery Smoke Alarm | SMI100

X-Sense Wireless Interconnected Smoke Detector Fire Alarm X...

X-Sense Smart Smoke Detector Fire Alarm with Replaceable Ba...

Kidde Hardwired Smoke & Carbon Monoxide Detector, 10-Year B...