---
product_id: 650964047
title: "BlackT Electrotech (BT51D) 120dB Wireless Door Bell & Window Alarm Sensor – 4in1 Smart Calling Bell for Home, Office Cabin & Property Security – No Wire, Easy Installation"
brand: "blackt electrotech"
price: "R398"
currency: ZAR
in_stock: true
category: "Blackt Electrotech"
url: https://www.desertcart.co.za/products/650964047-blackt-electrotech-bt51d-120db-wireless-door-bell-and-window-alarm
store_origin: ZA
region: South Africa
---

# 4-in-1 multi-use security 120dB piercing alert wireless, no-fuss install BlackT Electrotech (BT51D) 120dB Wireless Door Bell & Window Alarm Sensor – 4in1 Smart Calling Bell for Home, Office Cabin & Property Security – No Wire, Easy Installation

**Brand:** blackt electrotech
**Price:** R398
**Availability:** ✅ In Stock

## Summary

> 🚨 Stay ahead of intruders with the BT51D’s smart, loud, and wire-free security!

## Quick Answers

- **What is this?** BlackT Electrotech (BT51D) 120dB Wireless Door Bell & Window Alarm Sensor – 4in1 Smart Calling Bell for Home, Office Cabin & Property Security – No Wire, Easy Installation by blackt electrotech
- **How much does it cost?** R398 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.za](https://www.desertcart.co.za/products/650964047-blackt-electrotech-bt51d-120db-wireless-door-bell-and-window-alarm)

## Best For

- blackt electrotech enthusiasts

## Why This Product

- Trusted blackt electrotech brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Instant 120dB Alert:** Cut through the noise with a powerful alarm that demands attention—perfect for any entry point.
- • **4-in-1 Smart Security:** Combines doorbell, alarm sensor, emergency alert, and calling bell in one sleek device.
- • **Compact & Modern Design:** Seamlessly blends into your space while delivering maximum security with minimal effort.
- • **Versatile for Any Space:** Ideal for homes, offices, cabins, and shops—protect what matters wherever you are.
- • **Effortless Wireless Setup:** Peel, stick, and secure in seconds—ditch the wires and complicated installs for good.

## Overview

The BlackT Electrotech BT51D is a compact, battery-powered wireless doorbell and window alarm sensor delivering a piercing 120dB alert. Designed for easy peel-and-stick installation, it functions as a 4-in-1 security device—doorbell, alarm sensor, emergency alert, and calling bell—perfect for homes, offices, and cabins seeking hassle-free, effective protection.

## Description

BlackT Electrotech (BT51D) 120dB Wireless Door Bell & Window Alarm Sensor – 4in1 Smart Calling Bell for Home, Office Cabin & Property Security – No Wire, Easy Installation : desertcart.in: Home Improvement

## Features

- 🏠 [Wide Application – Home, Office & Cabin Use] Works as a wireless door bell for home, office cabin, or property security system. Perfect protection for doors, windows, and entry points without the need for wiring.
- 🚨 [Enhanced Security – 4in1 Function] Acts as a wireless calling bell + alarm sensor to safeguard your loved ones. Deters intruders effectively while ensuring peace of mind.
- 🔊 [125dB Loud & Clear Alert] Emits a powerful alarm sound that functions both as a door alarm security system and as an emergency alert bell. Guarantees instant attention during unauthorized entry.
- 🛠️ [No Wire – Easy Installation] No complicated setup required. This wireless alarm bell installs in seconds—just peel, stick, and secure. Ideal for flats, cabins, shops, and offices.
- 💡 [Smart & Reliable Design] Compact and versatile design fits seamlessly into modern homes. Doubles as a calling bell without wire while offering maximum protection with minimum effort.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0DBJ2R2K4 |
| Audible Noise | 120 Decibels |
| Battery Description | Alkaline |
| Best Sellers Rank | #8,545 in Home Improvement ( See Top 100 in Home Improvement ) #8 in Home Security Alarms |
| Brand | Blackt Electrotech |
| Built-In Media | magnet |
| Colour | white |
| Compatible Devices | Home Security System |
| Control Method | Touch |
| Country of Origin | China |
| Customer Reviews | 4.1 4.1 out of 5 stars (98) |
| Importer Contact Information | Blackt Electrotech |
| Item Type Name | Door sensor |
| Item Weight | 80 Grams |
| Manufacturer | Blackt Electrotech |
| Model Number | BT51D |
| Mounting Type | Door Mount |
| Number of Items | 1 |
| Packer Contact Information | Blackt Electrotech |
| Power Source | Battery Powered |
| Sensor Technology | Contact Sensor |
| Size | Small |

## Product Details

- **Battery Description:** Alkaline
- **Brand:** Blackt Electrotech
- **Colour:** white
- **Compatible Devices:** Home Security System
- **Power Source:** Battery Powered

## Images

![BlackT Electrotech (BT51D) 120dB Wireless Door Bell & Window Alarm Sensor – 4in1 Smart Calling Bell for Home, Office Cabin & Property Security – No Wire, Easy Installation - Image 1](https://m.media-amazon.com/images/I/51p8NfzarbL.jpg)

## Questions & Answers

**Q: 1. How does the alarm detect door or window opening?**
A: The sensor and magnetic strip work together. When the door or window opens and the magnetic connection breaks, the alarm activates instantly.

**Q: 2. How loud is the alarm sound?**
A: The alarm produces up to 120–125dB sound, helping alert occupants and deter unauthorized entry effectively.

**Q: 3. Is wiring required for installation?**
A: No, it is completely wireless. Simply attach the sensor and magnet using the included adhesive for quick installation.

**Q: 4. Where can this alarm be used?**
A: It is ideal for homes, apartments, offices, cabins, shops, warehouses, windows, doors, and other entry points.

**Q: 5. Can it be used as a calling bell?**
A: Yes, its 4-in-1 design allows it to function as a wireless calling bell as well as a door and window security alarm.

## Frequently Bought Together

- Blackt Electrotech (BT51D) 120dB 4in1 Wireless Door and Window Alarm Sensor for Home and Property Security
- Blackt Electrotech BT51A Wireless Motion Sensor Alarm with Intelligent Welcome Doorbell, Infrared Detector, Gate Alert Alarm, Remote Control, Easy Install for Daily Safety Protection

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*Product available on Desertcart South Africa*
*Store origin: ZA*
*Last updated: 2026-10-31*