1. Introduction
Thank you for choosing the Alonefire SV103 UV Flashlight. This powerful and versatile device is designed for a wide range of applications, from professional use to everyday tasks. Its high-quality construction and advanced features ensure reliable performance.
The SV103 features 3 high-quality 395nm UV LEDs, delivering an impressive 10W power consumption and 2800mW light output. Built with a durable aluminum alloy shell, it offers excellent heat dissipation and a long lifespan. The convenient USB-C charging port and included high-capacity rechargeable battery make it easy to power up. With an IPX5 waterproof rating, it's suitable for use in various conditions.
2. Safety Information
Please read all safety warnings and instructions carefully before using this product. Failure to follow these instructions may result in electric shock, fire, or serious injury.
- UV Radiation Warning: Do not look directly into the UV light source. UV light can be harmful to eyes and skin. Use appropriate eye protection (UV-blocking glasses) when operating for extended periods.
- Heat Warning: The flashlight may become warm during prolonged use due to its high power output. This is normal. Avoid direct contact with the hot surface for extended periods.
- Water Resistance: The flashlight has an IPX5 waterproof rating, meaning it is protected against low-pressure water jets from any direction. Do not immerse the flashlight in water.
- Battery Safety: Use only the provided rechargeable battery or a compatible replacement. Do not attempt to disassemble, puncture, or short-circuit the battery. Keep batteries away from fire and extreme temperatures.
- Children: Keep out of reach of children. This is not a toy.
3. Package Contents
Verify that all items are present and in good condition upon opening the package.
- Alonefire SV103 UV Flashlight
- Rechargeable Battery (18650 Li-ion 3.7V 2000mAh)
- USB-C Charging Cable

Image: The Alonefire SV103 UV Flashlight shown alongside its USB-C charging cable and the included rechargeable battery. The flashlight emits a purple UV light.
4. Setup
4.1. Battery Installation
- Unscrew the tail cap of the flashlight by turning it counter-clockwise.
- Insert the included 18650 rechargeable battery into the battery compartment with the positive (+) end facing towards the flashlight head (LEDs).
- Screw the tail cap back on clockwise until it is securely tightened.
4.2. Initial Charging
Before first use, fully charge the battery.
- Locate the USB-C charging port on the flashlight body. It is typically covered by a rubber flap for water resistance.
- Open the rubber flap and insert the small end of the USB-C charging cable into the flashlight's port.
- Connect the larger USB-A end of the cable to a USB power source (e.g., computer USB port, wall adapter, power bank).
- The charging indicator light will turn red while charging.
- Once fully charged (approximately 4-5 hours), the indicator light will turn green.
- Disconnect the charging cable and close the rubber flap to maintain water resistance.

Image: A close-up view of the Alonefire SV103 UV Flashlight head, highlighting the three high-quality UV LEDs. The text "3 x High quality UV LED" is visible.

Image: The Alonefire SV103 UV Flashlight connected to a laptop via its USB-C charging cable. An illustration shows the charging indicator light: red for charging, green for fully charged. Charging time is 4-5 hours, and battery life is 1-1.5 hours.
5. Operating Instructions
5.1. Power On/Off
Press the power button located on the side of the flashlight to turn it on. Press it again to turn it off.

Image: A hand holding the Alonefire SV103 UV Flashlight, demonstrating its compact size and ergonomic design for easy handling.
5.2. Applications of 395nm UV Light
The 395nm UV wavelength is highly effective for detecting fluorescent substances. Here are some common uses:
- Pet Urine Detection: Easily spot dried pet urine stains on carpets, rugs, and furniture that are invisible to the naked eye.
- Currency and Document Authentication: Verify the authenticity of banknotes, passports, and other official documents that contain UV security features.
- Scorpion Detection: Scorpions glow brightly under 395nm UV light, making them easy to spot in dark environments.
- Mineral and Gemstone Inspection: Identify certain fluorescent minerals and gemstones.
- Resin Curing: Accelerate the curing process of UV-sensitive resins and glues.
- Bed Bug Detection: Locate bed bugs and their eggs, which may fluoresce under UV light.
- Hygiene Inspection: Reveal hidden stains and unsanitary areas in hotel rooms, bathrooms, and kitchens.

Image: A collage demonstrating various applications of the UV flashlight. Examples include detecting pet urine on carpets, authenticating currency, identifying scorpions, illuminating fluorescent minerals, and revealing hidden stains on surfaces like toilets and hands.
5.3. Detachable Back Clip
The SV103 comes with a detachable back clip for convenient carrying. You can attach it to your belt, pocket, or backpack for easy access.

Image: The Alonefire SV103 UV Flashlight with its detachable back clip. One image shows it clipped to a person's belt, and another shows it clipped to a backpack, illustrating its portability for daily use.
5.4. 395nm vs 365nm UV Light
While both 395nm and 365nm UV lights are used for fluorescence, they have different characteristics:
- 395nm UV (Alonefire SV103): This wavelength is more visible to the human eye, producing a noticeable purple glow. It is excellent for general detection of fluorescent materials, such as pet stains, currency, and scorpions, where a strong visual indication is desired.
- 365nm UV: This wavelength is closer to the true "black light" spectrum, emitting less visible light and more pure UV. It is often preferred for professional applications requiring minimal visible light interference, such as forensic analysis, specialized mineral identification, and some industrial curing processes.

Image: A comparison chart showing the effect of 365nm versus 395nm UV light on different minerals. Under normal light, the minerals appear dull. Under 395nm UV, some minerals show a purple glow. Under 365nm UV, the same minerals exhibit a more vibrant and distinct fluorescence, indicating the difference in their applications.
6. Maintenance
- Cleaning: Wipe the flashlight body with a soft, damp cloth. Do not use abrasive cleaners or solvents.
- Lens Care: Gently clean the UV lens with a lens cleaning cloth to remove dust or smudges. Avoid touching the lens with bare fingers.
- Battery Care: If the flashlight will not be used for an extended period, remove the battery to prevent potential leakage. Store the battery in a cool, dry place.
- Storage: Store the flashlight in a dry environment, away from direct sunlight and extreme temperatures.
7. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Flashlight does not turn on. | Battery is dead or low. Battery inserted incorrectly. Tail cap is loose. | Charge the battery fully. Ensure battery is inserted with positive (+) end towards the head. Tighten the tail cap securely. |
| Light is dim. | Battery is low. Lens is dirty. | Recharge the battery. Clean the UV lens. |
| Charging indicator does not light up. | Charging cable not properly connected. USB power source is not active. Battery is already full. | Ensure cable is firmly connected to both flashlight and power source. Try a different USB port or power adapter. If battery is full, indicator will be green or off. |
| Flashlight gets hot. | Normal operation for high-power UV light. | This is expected. Avoid prolonged direct contact with the hot surface. Allow to cool down if necessary. |
8. Specifications
| Feature | Detail |
|---|---|
| Brand | ALONEFIRE |
| Model Number | SV103 395nm_EU |
| UV Wavelength | 395 nm |
| LED Type | 3 x High Quality UV LED |
| Power Output | 10 Watts |
| Light Output | 2800 mW |
| Material | Anodized Aluminum |
| Battery Type | 1 x 18650 Li-ion (Included) |
| Battery Capacity | 2000 mAh |
| Charging Port | USB-C |
| Charging Time | Approx. 4-5 hours |
| Battery Life | Approx. 1-1.5 hours (continuous use) |
| Waterproof Rating | IPX5 |
| Dimensions | 16 x 5.8 x 4.2 cm (Package) |
| Weight | 160 grams (Item) |
9. Warranty and Support
Alonefire products are manufactured to the highest quality standards. For warranty information and customer support, please refer to the purchase platform or contact Alonefire customer service directly.
Please retain your proof of purchase for warranty claims.
For further assistance, visit the official Alonefire website or contact your retailer.

