# Uni-T UT139B True RMS Digital Multimeter

**URL:** https://aio.lv/en/product--unit-ut139b--12478383
**Data updated:** 2026-05-22 07:21 (EEST)
**Category:** Measuring tools
**Manufacturer:** Unit
**Manufacturer code:** UT139B
**EAN:** 6935750521397
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 41.99 €
**Prices and availability valid until:** 2026-07-09 23:59
**Price without VAT (21%):** 34.70 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--unit-ut139b--12478383

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 25.06.2026 | free |
| Pickup points | 30.06.2026 | 1.99 EUR |
| Courier delivery to door | 30.06.2026 | 4.99 EUR |

## Summary description

The Uni-T UT139B is a professional-grade True RMS digital multimeter designed for precise electrical measurements. It features a robust build, reliable performance for voltage, current, and resistance testing, and is suitable for both industrial and domestic electrical troubleshooting. This versatile tool provides accurate readings for various electronic applications, ensuring safety and efficiency for technicians and hobbyists alike.

## Long description

The Uni-T UT139B is a professional-grade True RMS digital multimeter engineered for precise electrical measurements in various environments. This device combines robust construction with reliable performance, making it an essential tool for both industrial maintenance and domestic electrical troubleshooting. It features a clear display with a 31-segment analog bar graph, ensuring that technicians and hobbyists can monitor readings with high accuracy and efficiency.
Advantages
This multimeter stands out due to its True RMS capability, which ensures accurate measurements even with non-sinusoidal waveforms. The inclusion of the V.F.C. (Voltage Frequency Converter) function allows for stable readings in noisy electrical environments, such as near variable frequency drives. With its CAT III 600V safety rating, the device provides peace of mind during operation, while the NCV (Non-Contact Voltage) detection feature enables quick and safe identification of live wires without direct contact.
Suitable for
General electrical troubleshooting and maintenance
Testing voltage, current, and resistance in household appliances
Diagnosing electronic circuits and components
Field service and industrial equipment repair
Educational purposes and hobbyist electronics projects
This device may not be suitable for high-voltage industrial applications exceeding the 600V CAT III rating. Additionally, users requiring specialized features like high-precision laboratory-grade data logging or extremely high-frequency signal analysis may find the capabilities of this general-purpose multimeter limited.
Key specifications
Measurement range: DC/AC voltage up to 600V, DC/AC current up to 10A
Resistance measurement: up to 40 MΩ
Capacitance measurement: up to 99.99 mF
Frequency range: 10 Hz to 10 MHz
Safety rating: CAT III 600V
Display: 4000-count with analog bar graph and backlight
Power: 2x 1.5V AA batteries
To use the Uni-T UT139B, insert the provided batteries into the rear compartment. Connect the test leads to the appropriate input jacks based on the parameter you wish to measure. Select the desired function using the rotary dial, and use the range button to toggle between automatic and manual modes if necessary. The device will display the measured value on the LCD screen, and you can utilize the Data Hold or Max/Min buttons to capture specific readings during your testing process.
What to consider before purchase
Verify that the measurement ranges meet your specific project requirements
Ensure the CAT III 600V safety rating is sufficient for your intended work environment
Confirm that the physical size and weight are suitable for your portability needs
Check if the included accessories cover your immediate testing requirements
Always inspect your test leads for any signs of damage before use. Ensure the multimeter is set to the correct measurement mode before making contact with live circuits to prevent damage to the device or injury.

## FAQ

### How much does the Uni-T UT139B True RMS Digital Multimeter cost, and is it available for purchase?

The price is 41.99 € (valid at the time of publication and already includes all taxes). The item is available for order — 76 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 25.06.2026 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 Unit 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 Unit 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/12478383/68799263_large.webp