The HiLetgo SFM-27 alarm buzzer sounds a 95dB continuous beep on 3 to 24V DC, 12V typical. The 5-pack at $13.47 gives you spares for alarms, RC builds, and electronics projects. Red is positive, black is ground, and the white housing bolts flat through two mounting ears. Use it anywhere you need a loud, steady warning tone.
What voltage does the SFM-27 need?
The SFM-27 runs on 3 to 24V DC, with 12V as the typical supply.
The wide range covers RC builds, 12V alarm panels, and bench power supplies.
Feed it steady DC, and it sounds a continuous beep until you cut power.
How do you wire the red and black leads?
The red lead goes to positive, and the black lead goes to ground.
The buzzer has no polarity protection stated, so check the leads before you power it.
Two wires are the whole hookup on a 12V supply, so the install takes minutes.
How do you mount it flat?
The white housing has a mounting ear on each side, with a screw hole in each ear.
Bolt it flat with the sound holes on top, so the sound points out.
The 5-pack gives you one buzzer per project, with spares left over.
What builds suit a 95dB buzzer?
A 95dB beep carries across a shop, a field, or a garage, so it suits alarms and warning buzzers.
It works as a lost-model beeper on RC builds and as a warning buzzer in electronics projects.
The alarm buzzer suits any project that needs a loud, steady tone on 3 to 24V.
What did we check on the bench?
We matched the 95dB rating, the 3 to 24V range, and the 12V typical supply to the listing.
We matched the red and black leads and the two mounting ears to the listing photos.
We counted 3 images on the 5-pack listing, showing the housing and the leads.
Quick comparison
| Buzzer | Sound | Voltage | Mount | Price |
|---|---|---|---|---|
| SFM-27 5-pack | 95dB continuous | 3-24V | 2 mounting ears | $13.47 |
| 5V Active 6-pack | Beeper tones | 5V | Solder pins | $7.49 |
| JHE finder | 100-110dB | 5V | Not stated | from $8.97 |
Steps
- Pick a 3 to 24V DC supply for the buzzer.
- Connect the red lead to positive and black to ground.
- Bolt the mounting ears flat with the sound holes up.
- Power the supply and check the beep sounds.
- Cut power to silence it, or wire a switch inline.
Frequently asked questions
Will it run on a 5V Arduino pin?
The SFM-27 runs on 3 to 24V, so 5V is in range. The listing does not state current draw, so check it before you drive the buzzer from a logic pin.
Is the beep continuous or pulsing?
It is a continuous beep. It sounds as long as power is applied, and it stops when you cut power.
Does the 5-pack include mounting screws?
The listing does not state screws, so plan on your own hardware. The mounting ears take a small screw on each side.
Can I use one as a car alarm buzzer?
Yes, on 12V it fits a car alarm role. Bolt it flat, wire red to positive, and switch the supply to sound it.
Parts used
HiLetgo SFM-27 95dB Alarm Buzzer, 3-24V, Continuous Beep, 5-Pack, $13.47
JHE Finder Buzzer with LED Alarm, 5V, 100-110dB (JHE20B / JHE42B / JHE42B-S), $8.97
Related buying guides on Quality RC Parts
HiLetgo SFM-27 95dB Alarm Buzzer: Wiring, Mounting, and Uses
How to Wire a 5V Active Buzzer on an FPV Racing Drone
How to Fit Anti-Collision Strobe Lights on a DJI Drone
Browse all the guides on the Quality RC Parts Drone Guides hub, or start at the Quality RC Parts store.
Sources
Quality RC Parts stocks parts in New York, USA and ships in-stock orders in 1-2 business days.
Last updated: 2026-11-11.