1. Introduction
Thank you for choosing the DARKBEAM V4 UV 365nm Black Light Flashlight. This compact and powerful ultraviolet flashlight is designed for a variety of detection and curing applications. Its specialized 365nm wavelength and filtered lens provide pure UV light, making invisible substances visible. Please read this manual thoroughly before use to ensure proper operation and safety.

Figure 1: Two DARKBEAM V4 UV flashlights and their included USB charging cables.
2. Safety Information
- Eye Protection: Never look directly into the UV light beam. Prolonged exposure to UV light can be harmful to the eyes. Consider wearing UV protective eyewear during extended use.
- Skin Exposure: Avoid prolonged direct exposure of skin to UV light.
- Children: Keep the flashlight out of reach of children.
- Heat: The flashlight body may warm up during continuous operation. This is normal due to heat dissipation.
- Disposal: Do not dispose of the battery in fire. Follow local regulations for battery disposal.
3. Package Contents
Verify that all items are present in your package:
- DARKBEAM V4 UV 365nm Flashlight (quantity as purchased)
- Integrated Lithium-ion Battery
- USB Charging Cable (x2 for 2-pack)
- Lanyard (x2 for 2-pack)
4. Product Features
- Enhanced UV Light Source: Utilizes a 365nm UV light, which is a true invisible UV light. It appears less bright than 395nm to the naked eye but reveals fluorescent materials with a distinct blue-violet glow.
- Filtered 365nm UV Light: Equipped with a hardened black optical lens that filters out unwanted visible light, emitting a purer, more effective ultraviolet light for professional detection needs. This results in a clearer fluorescent effect with minimal visible purple light.
- Compact and Powerful: Small enough to fit on a keychain or in a pocket, offering a balance of size and performance for daily use. Includes a lanyard for easy carrying.
- Durable Construction: The housing is made from high-quality aluminum alloy, providing reliability and efficient heat dissipation.
- Integrated Rechargeable Battery: Powered by a built-in rechargeable battery, offering approximately 1 hour of continuous operation on a full charge.

Figure 2: The specialized black filter lens blocks ambient visible light, allowing only pure UV light to pass through for enhanced detection.

Figure 3: The aluminum alloy body is designed for efficient heat dissipation during operation.
5. Setup and Charging
5.1 Initial Charge
Before first use, fully charge the flashlight. The integrated battery requires approximately 1 hour for a full charge.
5.2 Charging Instructions
- Locate the USB charging port on the flashlight.
- Connect the provided USB charging cable to the flashlight's port.
- Connect the other end of the USB cable to a compatible USB power source (e.g., 5V/2A adapter, power bank, laptop, car charger).
- The indicator light will show red while charging.
- The indicator light will turn green when the battery is fully charged.
- Disconnect the charging cable once fully charged.

Figure 4: The flashlight features a USB charging port and indicator lights for charging status (red for charging, green for full).
6. Operating Instructions
- To turn the flashlight ON, press the power button located at the end of the flashlight.
- To turn the flashlight OFF, press the power button again.
- The flashlight operates in a single mode (ON/OFF).

Figure 5: The compact design allows for easy portability, fitting into small bags or pockets.
7. Applications
The DARKBEAM V4 UV 365nm flashlight is suitable for a wide range of applications:
- Pet Stain Detection: Easily locate dried pet urine, feces, and vomit on carpets, rugs, and upholstery.
- Authenticity Verification: Identify counterfeit documents, currency, and official IDs by revealing hidden security features.
- Mineral and Gemstone Inspection: Detect fluorescent minerals, amber, and uranium glass.
- Resin Curing: Accelerate the curing process of UV-sensitive resins, such as those used in 3D printing or jewelry making.
- Leak Detection: Identify leaks in HVAC systems, automotive fluids, and other machinery when used with UV-reactive dyes.
- Hygiene Inspection: Reveal hidden stains and unsanitary areas in hotel rooms, bathrooms, and kitchens.
- Scorpion Hunting: Scorpions fluoresce brightly under 365nm UV light, making them easy to spot in the dark.
- Cat Ringworm Detection: Aid in the detection of certain types of fungal infections (ringworm) on pets, which may fluoresce under UV light.
- UV Reactive Art: Illuminate UV-reactive paints, body art, and fluorescent materials for artistic and decorative purposes.

Figure 6: The flashlight can be used to detect ringworm on a cat and pet urine stains on surfaces.

Figure 7: Effectively reveals hidden pet urine stains, making cleaning simpler.

Figure 8: The UV light makes invisible stains visible, aiding in thorough cleaning and inspection.

Figure 9: Examples of diverse applications including detecting toilet stains, identifying leaks, illuminating scorpions, and revealing fluorescent agents.

Figure 10: Further applications include ore detection, currency verification, illuminating body art, and detecting cat ringworm.
8. Maintenance
- Cleaning: Wipe the flashlight body with a soft, damp cloth. Do not use abrasive cleaners or solvents.
- Lens Care: Gently clean the lens with a lens cleaning cloth to maintain optimal light output.
- Storage: Store the flashlight in a cool, dry place when not in use. Avoid extreme temperatures.
- Battery: Recharge the battery regularly, even if not in frequent use, to prolong its lifespan.
9. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Flashlight does not turn on. | Battery is depleted. | Charge the flashlight fully (refer to Section 5.2). |
| Flashlight does not charge. | Faulty USB cable or power source. | Try a different USB cable or power adapter. Ensure connections are secure. |
| UV light appears dim or weak. | Low battery or dirty lens. | Charge the flashlight. Clean the lens with a soft cloth. |
10. Specifications
| Specification | Detail |
|---|---|
| Item Model Number | V4 |
| Product Dimensions (L x W x H) | 9 x 2.15 x 2.15 cm (3.54 x 0.85 x 0.85 inches) |
| Weight | 56 grams (1.98 ounces) |
| Material | Aluminum |
| Power Source | Battery Powered |
| Light Source Type | UV 365nm LED |
| Battery Type | Integrated Lithium-ion |
| Voltage | 5 Volts |
| Manufacturer | DARKBEAM |
| Country of Origin | China |
11. Warranty and Support
For any questions, concerns, or assistance with your DARKBEAM V4 UV 365nm Flashlight, please contact the seller directly through the Amazon platform. The seller offers 7x24 hours online response. To contact the seller, navigate to your order details and click on "Ask a question" in the seller profile.




