SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery

SITERWELL GS509A is a battery-powered photoelectric smoke detector with a replaceable 9V battery, test/mute button, and low-battery warning. The listing calls out a 10-year product life, but describes that period as dependent on continuous battery replacement, not a 10-year battery.

At a glance

Photoelectric sensing is presented as suited to detecting slow-smoldering fires that produce light smoke.
The listing describes a test/mute button and says weekly testing is required.
A low-battery warning is claimed. The listed battery is a 9V type.
The product life claim depends on continuous battery replacement. The listing does not describe this as a 10-year battery.

Price

$113.53Save 14%

Reference price: ~~$132.77~~

Price checked: Nov 13, 2026

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Pros and cons

Pros

Replaceable-battery design avoids relying on a sealed battery for the detector's claimed product life.
The test/mute button and low-battery warning provide stated functions for routine checking and battery maintenance.
A mounting bracket and magnetic fastening kit are listed in the package contents.

Cons

The claimed 10-year product life requires continuous battery replacement, so it does not mean one battery lasts ten years.

Technical specifications

11 specifications

Identity
Brand	SITERWELL
Model	GS509A

Power and sensing
Power configuration	Battery Powered
Sensor type	Photoelectric
Alarm	Audible

Dimensions and installation
Dimensions listed	3.93"D x 3.93"W x 1.39"H

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

Appearance
Color	White
Product style	Replaceable Battery (NEW)

What to know before buying

The listing says the detector has a one-year 9V battery and a ten-year product life with continuous battery replacement. Treat these as separate claims, not a ten-year battery-life promise. Follow the stated weekly test instruction and applicable smoke-alarm placement guidance.

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

Buyers seeking a battery-powered, replaceable-battery smoke alarm with photoelectric sensing and a test/mute button.
Households wanting the stated low-battery warning and mounting options, including a magnetic fastening kit.

Less suited to

Buyers specifically seeking a sealed 10-year battery or a detector that needs no battery replacement.
Buyers who need a carbon monoxide detector or a hardwired/interconnected alarm, neither of which is specified for this model.

SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery · 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 reports that buyers appreciate easy mounting, portability, and the detector's loud sound, while experiences with installation and magnetic mounting are mixed. Some also say the battery is not a ten-year battery and find the beeping annoying. That battery concern is consistent with the listing's distinction between a one-year battery and a ten-year product life requiring replacement. Aggregate ratings lean positive overall, but do not establish how well any individual detector performs.

Positive themes

Customers report that the detector is easy to mount and portable.

Negative themes

Some customers describe the beeping as annoying and report that the battery is not a ten-year battery.

Mixed feedback

Feedback on installation and magnetic mounting is mixed, including reports of adhesive not holding and missing magnetic pieces.
Customers describe the alarm as loud, which may be useful for audibility but bothersome in some settings.