# GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery

## GS509A-2NCDR: Smoke detection with simple screw mounting

The SITERWELL GS509A-2NCDR is a standalone photoelectric smoke alarm that mounts with the supplied mounting plate, screws and wall plugs, making it a practical choice for straightforward home installation. Its replaceable-battery design keeps routine maintenance accessible, with single and multipack options for planning your alarm locations.

### Key features

-   **Photoelectric smoke sensing:** Detects smoke using an optical sensor.
-   **Screw mounting:** Fixes to a ceiling or wall with the supplied mounting plate, screws and wall plugs, following the supplied instructions.
-   **Replaceable battery:** Maintain power with the battery type specified for your unit.
-   **10-year product life:** Product service life is separate from battery life; batteries need replacement during use.
-   **Test button:** Check operation as part of your regular alarm maintenance.
-   **Audible alarm:** Rated at ≥85 dB(A) at 10 feet (3.05 m), as stated in the product manual.
-   **Low-battery warning:** A signal reminds you when the battery needs attention.

### Choose your home safety setup

For separate carbon monoxide detection, add the [Plug-in CO alarm](/products/gs846a-plug-in-carbon-monoxide-detector); each device operates independently. Prefer a smoke alarm with a built-in battery designed for 10 years? Compare the [GS525A 10-year battery smoke alarm](/products/gs525a-10-year-battery-smoke-detector).

For setup, placement and routine testing, follow the instructions supplied with your alarm. Browse our [product user manuals](/pages/user-manuals) for model-specific guidance. For [the difference between photoelectric and ionization sensing](https://store.siterwellhome.com/blogs/all-blogs/photoelectric-vs-ionization-smoke-detector), see our guide.

### Protect Your Delivery

For extra protection against eligible physical loss, external damage or shortage while your order is in transit—and eligible theft after delivery within the coverage term—consider adding optional [**Shipsurance shipping insurance**](/pages/shipsurance) when it is offered at checkout. If you purchased this coverage and a shipping-related issue occurs, review the coverage rules and contact **SureCircle** first to file a claim or check claim status. Product setup, technical support, product defects and manufacturer-warranty questions remain with SITERWELL.

### Customer Service

**U.S. Customer Service Hotline:** [+1 800-710-7321](tel:+18007107321)  
Monday–Friday, 9:00 AM–6:00 PM (EST)

## Details

- **Price:** 15.99 USD - 326.99 USD
- **Vendor:** Siterwell
- **Tags:** 10-Year Battery, Smoke alarms, Standalone

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| 2 Pack | 31.98 USD | In stock |
| 4 Pack | 63.96 USD | In stock |
| 6 Pack | 95.54 USD | In stock |
| 1 Pack | 15.99 USD | In stock |
| 8 Pack | 125.99 USD | In stock |
| 10 Pack | 147.99 USD | In stock |
| 12 Pack | 166.99 USD | In stock |
| 24 Pack | 326.99 USD | In stock |

## Images

- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery
- GS509A-2NCDR Photoelectric Smoke Detector with 9V Battery

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> Source: [siterwell.us](https://store.siterwellhome.com/products/gs509a-2ncdr-photoelectric-smoke-detector)
> Updated: 2026-10-29