# Door contact sensor BLOW 4557# (reed switch) HO-03G brown

**URL:** https://aio.lv/en/product--blow-4557--11863414
**Data updated:** 2026-03-09 17:40 (EET)
**Category:** Smart Sensors
**Manufacturer:** BLOW
**Manufacturer code:** 4557#
**EAN:** 5900804099000
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 6.49 €
**Prices and availability valid until:** 2026-07-17 23:59
**Price without VAT (21%):** 5.36 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--blow-4557--11863414

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 13.07.2026 | free |
| Pickup points | 16.07.2026 | 1.99 EUR |
| Courier delivery to door | 16.07.2026 | 4.99 EUR |

## Summary description

Wired door contact sensor BLOW 4557# (HO-03G) in brown. A simple reed-switch style sensor designed to detect opening and closing of doors or windows. Suitable for use with alarm systems, home security setups, and access monitoring. Small form factor for discreet mounting on frames and sashes; provides a contact closure signal when the magnet is separated.

## Long description

The BLOW door contact sensor HO-03G (reed switch) in brown is a wired magnetic sensor designed to detect the opening and closing of doors or windows. Its compact, low-profile housing allows discreet installation on door and window frames and sashes. The sensor operates as a normally-closed reed switch that changes state when the magnet is separated, producing a contact closure signal compatible with standard alarm control panels and monitoring devices.
Advantages
The device offers reliable mechanical switching with minimal electronic complexity, ensuring long-term stability and predictable performance. Its small dimensions and neutral brown finish make it suitable for unobtrusive mounting on wooden or painted surfaces. As a wired sensor, it provides a continuous connection to security systems without the need for batteries, reducing maintenance requirements and offering consistent signal transmission.
Suitable for
Wired alarm systems for residential and small commercial properties
Perimeter protection of doors and windows
Access monitoring in offices, storage rooms, or cabinets
Retrofit installations where discrete, low-profile sensors are required
Key specifications
Type: Reed switch (magnetic contact)
Connection: Wired (contact closure output)
Color: Brown
Mounting: Surface mount on frame and sash
Form factor: Compact, low-profile housing for discreet installation
Operating principle: Changes contact state when magnet is separated
How to use
Install the sensor body on the fixed frame and the magnet on the moving sash so that the two parts align when the door or window is closed. Connect the sensor wires to the corresponding input on the alarm control panel or monitoring device following the panel manufacturer’s wiring diagram for normally-closed contacts. Verify correct operation by opening and closing the door or window and confirming the panel registers the change of state. Secure the components with screws or adhesive according to the mounting surface and ensure wiring is routed to avoid pinch points.
Usage recommendations
Place the sensor where the magnet and reed switch meet without gaps larger than the manufacturer’s suggested alignment — proper alignment ensures reliable detection. Avoid installing the sensor near strong electromagnetic sources or where mechanical strain may damage wires. For exposed exterior doors, use protected routing and suitable sealants to prevent moisture ingress into cable entry points.

## FAQ

### How much does the Door contact sensor BLOW 4557# HO-03G cost, and is it available for purchase?

The price is 6.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 10 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance.

### If I order this product today, when will I receive my order?

If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on 13.07.2026 at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation.

### What payment options are available?

AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay. All transactions are 100% secure and encrypted.

### Can this product be purchased for a company (with VAT)?

Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout.

### What is the warranty period?

All BLOW products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized BLOW service centers and through AiO.lv

### Can the product be returned after purchase?

Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return.

### Where should I contact for warranty service?

For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty

## Image

https://aio.lv/img/cache/product/11863414/67261937_large.webp