Can I connect this siren directly to a 220V wall outlet?

No, this siren operates strictly on 12V DC power, so you must use a 12V power adapter (transformer) to connect it to a standard 220V AC mains supply.

How do I wire this siren to my security system?

You must connect the Red wire to the positive (+) 12V alarm output of your security panel, and the Black wire to the negative (-) ground terminal.

Is this siren suitable for outdoor installation?

While the plastic casing is durable, it does not have an official waterproof rating, so it must be installed under an eave or inside a protective housing if used outdoors to prevent rain damage.

Can I change the alarm sound on this siren?

No, this is a dedicated 1-tone siren, meaning it produces a single, continuous high-pitched alarm sound that cannot be changed or customized.

Can I buy this alarm siren today at your Hong Kong store?

Yes, this 12V 20W electronic siren is regularly stocked at our Sun Cheong Computer Co. Ltd. physical store in Sham Shui Po for immediate purchase and pickup.

12V 20W Electronic Alarm Siren | 1-Tone Security Horn

Name: 12V 20W Electronic Alarm Siren | 1-Tone Security Horn
Brand: Sun Cheong Computer Company Limited
SKU: 21PS001972
Price: 39.0 HKD
Availability: InStock

Short Product Description

The 12V 20W Electronic Alarm Siren is a high-decibel, 1-tone warning horn designed for home security systems, vehicle alarms, and industrial alerts. Operating on a standard 12V DC power supply, this compact yet powerful siren delivers a piercing continuous alarm to deter intruders instantly. Weighing just 195g and featuring a pre-drilled metal mounting bracket, it ensures quick and secure installation. Available in-stock at Sun Cheong Computer Co. Ltd. (新昌電腦有限公司) in Sham Shui Po, our technical team recommends this reliable siren for DIY security upgrades and professional CCTV alarm integrations.

Key Features

20W High-Output Speaker: Delivers a piercing, high-decibel alarm to effectively deter intruders and alert personnel.
Standard 12V DC Operation: Easily integrates with standard CCTV DVR alarm outputs, car batteries, and access control panels.
Continuous 1-Tone Siren: Produces a single, unmistakable warning tone that cuts through background noise.
Adjustable Metal Bracket: Features a pre-drilled, tiltable metal base for secure and flexible mounting on any flat surface.
50cm Pre-Stripped Cable: Comes with a generous half-meter of wiring, making it easy to connect to terminal blocks or relays without extra splicing.

Full Product Description

Piercing 1-Tone Alarm for Maximum Security

This 20W electronic siren delivers a continuous, high-decibel single-tone alarm that commands immediate attention and deters potential intruders. Unlike standard low-power buzzers, the 20-watt internal speaker projects sound over long distances, making it highly effective for noisy industrial environments, large warehouses, or outdoor perimeters. When integrated with a motion sensor or access control panel, it provides an unmistakable auditory warning the moment a security breach is detected.

Easy 2-Wire Installation & Versatile Mounting

Wiring this alarm horn into your existing security network is incredibly straightforward thanks to the pre-stripped 50cm red and black pigtail cable. The unit features a robust, adjustable metal bracket with multiple pre-drilled holes, allowing you to mount it securely to walls, ceilings, or vehicle chassis using standard screws. Its compact 8cm x 7.5cm footprint ensures it can be installed discreetly under eaves or inside security junction boxes without drawing unwanted attention.

Pro Tip from Our Technicians

Always ensure your 12V DC power supply can handle the current draw of a 20W device (we recommend a power adapter rated for at least 12V 2A). Our Sham Shui Po security installation specialists remind you to strictly observe polarity during wiring: the Red wire must connect to Positive (+), and the Black wire to Negative (-). Reversing the polarity will prevent the siren from sounding and may damage the internal circuitry.

Technical Specifications

Product Type: Electronic Alarm Siren / Warning Horn
Operating Voltage: 12V DC
Power Output: 20W
Sound Type: 1 Tone (Continuous Siren)
Wiring: Red (Positive +), Black (Negative -)
Cable Length: Approx. 50cm
Dimensions: 8cm (Length) x 7.5cm (Diameter)
Weight: 195g
Mounting: Adjustable Metal Bracket with Pre-drilled Holes

Delivery Options

Local delivery within Hong Kong and in-store pickup.
Free shipping for orders of HK$400 or above; HK$35 shipping fee for orders below HK$400.
Shipped by SF Express, usually dispatched the same day for orders confirmed before 6:00 PM (Mon–Sat).
Estimated delivery time: 1–3 business days after dispatch (Hong Kong).
In-store pickup details (location and time) will be confirmed by email or phone message.
Delivery times are estimates and may be affected by weather or unforeseen circumstances.

FAQ Section

Can I connect this siren directly to a 220V wall outlet?No, this siren operates strictly on 12V DC power, so you must use a 12V power adapter (transformer) to connect it to a standard 220V AC mains supply.
How do I wire this siren to my security system?You must connect the Red wire to the positive (+) 12V alarm output of your security panel, and the Black wire to the negative (-) ground terminal.
Is this siren suitable for outdoor installation?While the plastic casing is durable, it does not have an official waterproof rating, so it must be installed under an eave or inside a protective housing if used outdoors to prevent rain damage.
Can I change the alarm sound on this siren?No, this is a dedicated 1-tone siren, meaning it produces a single, continuous high-pitched alarm sound that cannot be changed or customized.
Can I buy this alarm siren today at your Hong Kong store?Yes, this 12V 20W electronic siren is regularly stocked at our Sun Cheong Computer Co. Ltd. physical store in Sham Shui Po for immediate purchase and pickup.

Target Users / Applications

CCTV installers adding audible deterrents to DVR/NVR alarm output relays.
DIY car and motorcycle enthusiasts building custom 12V anti-theft vehicle alarm systems.
Factory safety officers installing loud warning horns for emergency evacuation push-buttons.