# Door contact sensor BLOW 4933# model HO-03i — magnetic reed switch for alarm systems

**URL:** https://aio.lv/en/product--blow-4933--11863393
**Data updated:** 2026-03-09 17:40 (EET)
**Category:** Smart Sensors
**Manufacturer:** BLOW
**Manufacturer code:** 4933#
**EAN:** 5900804099017
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 14.99 €
**Prices and availability valid until:** 2026-07-14 23:59
**Price without VAT (21%):** 12.39 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--blow-4933--11863393

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 08.07.2026 | free |
| Pickup points | 13.07.2026 | 1.99 EUR |
| Courier delivery to door | 13.07.2026 | 4.99 EUR |

## Summary description

Wired door contact sensor BLOW 4933# (HO-03i) is a magnetic reed switch designed for security and alarm systems. It detects door or window opening by separating the magnet and reed contact. Compact form factor allows surface mounting on frames and sashes. Typical use: perimeter intrusion detection, access monitoring and integration with control panels.

## Long description

Wired door contact sensor BLOW HO-03i is a magnetic reed switch intended for integration with alarm and security systems. The sensor detects opening of doors or windows by monitoring the relative position of a magnet and a reed contact: when the magnet moves away, the reed opens and the sensor signals an alarm input. The compact plastic housing is designed for surface mounting on door/window frames and sashes and provides a simple, low-profile solution for perimeter intrusion detection and access monitoring.
Advantages
The device offers simple wired connectivity compatible with standard alarm control panels and low power consumption due to its passive reed mechanism. Its compact dimensions and lightweight housing allow discreet installation on most door and window types without structural changes. The magnetic operation provides reliable, maintenance-light performance with minimal risk of false activation from power interruptions.
Suitable for
Perimeter intrusion detection on external and internal doors
Window opening monitoring in residential and commercial premises
Access control monitoring for cabinets, gates, and secondary entrances
Integration with alarm control panels and wired security loops
Key specifications
Operating principle: magnetic reed contact (normally closed / opens when magnet separated)
Connection type: wired two/three conductor interface for alarm zones
Mounting: surface mount on frames and sashes
Housing material: durable plastic enclosure
Dimensions: compact form factor suitable for tight mounting locations
Environmental suitability: designed for indoor use in typical residential and commercial environments
How to use
Install the sensor body on the stationary frame and align the magnet element on the moving sash so that the two parts are adjacent when the door or window is closed. Connect the sensor leads to the alarm panel zone input following the panel manufacturer’s wiring scheme, observing polarity if required and including any tamper or end-of-line resistors recommended by the control panel. After installation, test the zone by opening and closing the door or window to confirm the panel registers open and closed states correctly.
Usage recommendations
Place the sensor where the magnet and reed align within the specified gap for reliable detection, avoid mounting where heavy vibration or direct water exposure occurs, and periodically inspect mounting and wiring for secure attachment. For best results, follow the alarm panel manufacturer’s guidelines for zone termination and any required supervision or tamper circuits.

## FAQ

### How much does the Door contact sensor BLOW 4933# HO-03i cost, and is it available for purchase?

The price is 14.99 € (valid at the time of publication and already includes all taxes). The item is available for order — 46 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 08.07.2026 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/11863393/67261775_large.webp