SITERWELL GS509A 12-Pack Photoelectric Smoke Detectors

Detectors: The SITERWELL GS509A is a battery-powered, photoelectric smoke alarm sold in a 12-pack. Its replaceable 9V battery and low-battery warning suit buyers who want alarms they can maintain by changing batteries, while the stated ten-year product life is not a ten-year battery life.

At a glance

Photoelectric sensing is described as intended to detect slow, smoldering fires that produce light smoke and little heat.
A test/mute button is provided, and the listing calls for weekly testing.
The listing describes an audible alarm louder than 85 dB and a low-battery signal.
Replaceable 9V battery design means the stated ten-year product life depends on continuous battery replacement.

Price

$168.66Save 11%

Reference price: ~~$188.76~~

Price checked: Nov 12, 2026

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Pros and cons

Pros

A 12-pack can cover multiple locations when a larger number of alarms is needed.
Replaceable batteries avoid relying on a sealed ten-year battery for the device's entire stated product life.
The photoelectric sensor is positioned for detecting slow, smoldering fires.
The listed test/mute button and low-battery warning support routine upkeep.

Cons

The included 9V battery is described as lasting one year, so battery replacement is an ongoing maintenance task.
The listing calls for weekly testing, which requires regular attention.

Technical specifications

12 specifications

Identity
Brand	SITERWELL
Model	GS509A
Pack quantity	12

Power and detection
Power configuration	Battery Powered
Sensor type	Photoelectric
Alarm	Audible
Battery life stated	1-year 9V battery

Dimensions and installation
Dimensions listed	3.93"D x 3.93"W x 1.37"H

Materials and operating conditions
Material listed	Polycarbonate
Color	White
Operating humidity	10-95% RH non-condensing
Upper temperature rating	37.8 °C

What to know before buying

The ten-year claim refers to product life with continuous battery replacement, not a ten-year battery. The listing also says the supplied 9V battery lasts one year. Follow the stated weekly testing guidance and applicable installation requirements.

What’s in the box

Included

Smoke alarm
1 9V carbon-zinc battery
User manual
Mounting screws
Magnetic fastening kit

Who is it for?

A good fit for

Households needing a 12-pack of battery-powered smoke alarms with replaceable batteries.
Buyers looking for photoelectric smoke detection and willing to perform weekly tests and replace batteries.

Less suited to

Buyers seeking a sealed battery rated to last ten years without replacement.
Buyers who need a carbon monoxide detector or hardwired, interconnected alarms, which are not specified for this product.

SITERWELL GS509A 12-Pack Photoelectric Smoke Detectors · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.4 / 5 · 762 ratings

5 stars75%75%
4 stars12%12%
3 stars5%5%
2 stars2%2%
1 star6%6%

Customer feedback highlights easy mounting, portability and perceived value, but reports mixed experiences with installation and magnetic mounting. Some customers say the battery is not a ten-year battery, consistent with the listing's one-year 9V battery claim and replaceable-battery design. The alarm's loudness is appreciated by some and viewed negatively by others, while beeping is also criticized. Buyers should weigh these reports against the need for periodic battery changes and weekly testing.

Positive themes

Customers describe the alarms as easy to mount and portable, with some finding them useful for older people.

Negative themes

Some customers describe the beeping as annoying.

Mixed feedback

Installation and magnetic mounting experiences vary, including reports of adhesive not holding and missing magnetic pieces.
Battery feedback is mixed, with customers noting the battery is not a ten-year battery.
Feedback on noise is mixed, including reports that the alarm is fairly loud.