# Fnirsi FNB58 Digital USB Voltmeter and Cable Tester with LCD Display

**URL:** https://aio.lv/en/product--fnirsi-fnb58--12426867
**Data updated:** 2026-05-10 04:43 (EEST)
**Category:** Cable testers
**Manufacturer:** Fnirsi
**Manufacturer code:** FNB58
**EAN:** 5905156102200
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 44.49 €
**Prices and availability valid until:** 2026-07-16 23:59
**Price without VAT (21%):** 36.77 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--fnirsi-fnb58--12426867

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 03.07.2026 | free |
| Pickup points | 08.07.2026 | 1.99 EUR |
| Courier delivery to door | 08.07.2026 | 4.99 EUR |

## Summary description

The Fnirsi FNB58 is a professional digital USB tester designed for monitoring voltage, amperage, and wattage. Featuring a clear LCD display, it supports USB Type-A connections, making it an essential tool for diagnosing power delivery, testing cable quality, and troubleshooting charging issues for various electronic devices and power adapters.

## Long description

The Fnirsi FNB58 is a professional digital USB voltmeter and cable tester designed to monitor voltage, amperage, and wattage in real-time. By connecting this device between a power source and your electronics, you can accurately measure electrical parameters including volts, amps, watts, ohms, and temperature, while also tracking total energy transfer. It features a 2-inch LCD display with multiple interface views and supports connectivity with Windows software and Android applications for advanced data analysis.
Advantages
This versatile tester provides comprehensive diagnostic capabilities for various USB standards, including USB-C, Micro USB, and USB-A. It excels at identifying fast-charging protocols such as QC2.0/3.0, FCP/SCP, AFC, USB PD2.0/3.0, and VOOC/WARP, while also reading E-marker chips in USB-C cables to verify cable quality and performance. Its ability to store data and interface with external software makes it an essential tool for troubleshooting complex charging issues and verifying power delivery efficiency.
Suitable for
Monitoring real-time charging voltage and current
Testing cable quality and data transfer capabilities
Verifying fast-charging protocol compatibility
Diagnosing power delivery issues in chargers and power banks
Reading E-marker chip information in USB-C cables
When it may not be suitable
This device is intended for technical diagnostic purposes and may be overly complex for casual users who only require basic charging status. It is not designed for high-voltage industrial power systems outside of standard USB specifications.
Key specifications
Display: 2-inch LCD
Supported connections: USB Type-A, USB-C, Micro USB
Measured parameters: Voltage, amperage, wattage, resistance, temperature, energy capacity
Protocol support: QC2.0/3.0, FCP/SCP, AFC, USB PD2.0/3.0, VOOC/WARP, Super VOOC 1.0/2.0
Connectivity: Windows software and Android app support
How to use
To use the Fnirsi FNB58, connect the tester directly into your power source or charger, then plug your USB cable and device into the tester. The device will automatically begin measuring the electrical flow. Use the interface buttons to toggle between the different display views on the LCD screen to view specific metrics. For advanced data logging and analysis, connect the tester to a Windows computer or a compatible Android device using the provided software or application.
What to consider before purchase
Ensure your devices utilize the supported USB standards
Check compatibility with your specific operating system for software features
Verify if you require advanced protocol testing or simple voltage monitoring
Usage recommendations: Always ensure the tester is securely connected to both the power source and the device to prevent intermittent readings. When testing high-power devices, ensure the cable being tested is rated for the required amperage to avoid inaccurate results or potential overheating.

## Specifications

| Feature | Value |
|---|---|
| Product colour | Silver |
| Built-in display | Yes |
| Display type | LCD |
| Power connectors supported | USB Type-A |
| Testing type | Amperage, Voltage, Wattage |

## FAQ

### How much does the Fnirsi FNB58 Digital USB Voltmeter and Cable Tester cost, and is it available for purchase?

The price is 44.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 32 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 03.07.2026 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 Fnirsi 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 Fnirsi 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/12426867/68733662_large.webp