# Door contact sensor BLOW 4931# (reed switch) model HO-03D, wired magnetic door/window sensor

**URL:** https://aio.lv/en/product--blow-4931--11863466
**Data updated:** 2026-03-09 17:40 (EET)
**Category:** Sensors & Detectors
**Manufacturer:** BLOW
**Manufacturer code:** 4931#
**EAN:** 5900804098942
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 16.99 €
**Prices and availability valid until:** 2026-07-26 23:59
**Price without VAT (21%):** 14.04 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--blow-4931--11863466

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 17.07.2026 | free |
| Pickup points | 22.07.2026 | 1.89 EUR |
| Courier delivery to door | 22.07.2026 | 4.99 EUR |

## Summary description

Wired magnetic door/window contact sensor BLOW 4931# (HO-03D) is a reed-switch type detector for monitoring open/closed state of doors or windows. Designed for integration with alarm and security systems, it provides a simple magnetic contact and compact mounting. Typical use includes perimeter protection, entry monitoring and system arming/disarming triggers.

## Long description

Wired magnetic door/window sensor BLOW 4931# (model HO-03D) is a reed-switch type contact sensor designed to detect the open or closed state of doors and windows. The detector consists of a compact magnet and a separate reed-switch housing connected by wiring, enabling reliable state monitoring when integrated into wired alarm and security systems. The device provides a straightforward normally closed or normally open contact output depending on installation and wiring, allowing it to act as a trigger for perimeter protection, entry monitoring or arming/disarming functions.
Advantages
The sensor features a compact form factor that fits most door and window frames and a simple reed-switch mechanism that offers low-power, long-term reliability. Its wired connection eliminates battery management and reduces false alarms caused by RF interference. The separate magnet and contact housing allow flexible positioning for flush or surface mounting, while the straightforward electrical behavior simplifies integration with a wide range of wired control panels and alarm inputs.
Suitable for
Perimeter protection of residential and commercial premises
Monitoring individual doors and windows for unauthorized opening
Integration with wired alarm panels, access control systems, and automation controllers
Use as a zone trigger for arming and disarming sequences
Key specifications
Detector type: reed-switch magnetic contact
Mounting: surface-mounted or inset mounting depending on installation
Connection: wired contact leads for integration into alarm circuits
Operating principle: magnet actuates reed switch to indicate open/closed state
Housing: compact plastic enclosure suitable for door and window frames
Environmental suitability: intended for indoor use in typical residential and commercial environments
How to use
Install the contact housing on the fixed frame and the magnet on the moving leaf so that the magnet aligns with the reed-switch when the door or window is closed. Route and secure the sensor wiring to the alarm panel or control input, following the panel manufacturer’s wiring conventions for normally closed or normally open circuits as required. Test the sensor by opening and closing the door or window and verifying the corresponding state change at the control panel. Ensure mounting surfaces are clean and flat to maintain consistent gap and reliable switching.
Usage recommendations
Place the sensor where the magnet and contact can maintain a consistent gap when closed; avoid areas exposed to moisture or direct weathering. For reliable performance, follow the alarm panel’s wiring and tamper-monitoring guidelines and perform periodic functional checks as part of routine security maintenance.

## FAQ

### How much does the Door contact sensor BLOW 4931# HO-03D cost, and is it available for purchase?

The price is 16.99 € (valid at the time of publication and already includes all taxes). The item is available for order — 1 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 17.07.2026 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/11863466/67262031_large.webp