DESCRIPTION
The HTO9V31 VFL Pen is a premium visual fault locator designed for accurate and efficient fiber optic testing. With its bright 650 nm laser, it detects and highlights breaks, bends, and weak connections in fiber cables. Its durable aluminum alloy body, low battery indicator, and ergonomic design make it perfect for both field and laboratory applications. The universal 2.5mm connector ensures compatibility with a wide range of fiber optic interfaces, making it a versatile tool for technicians.
Feature Details

- Compact & Portable: Small, lightweight design allows for easy transportation and convenient use.
- Robust Construction: Made with a crash-proof, dust-proof aluminum body for enhanced durability.
- Powerful Light Source: 30 mW output with 650 nm wavelength ensures clear fault identification.
- Universal Adapter: Works with SC, FC, ST, and LC connectors for single-mode and multimode fibers.
- Long Battery Life: Operates for up to 50 hours with two AA batteries (not included).
Product Specifications
| Attribute | Details |
| Material | Aluminum Alloy |
| Wavelength | 650 nm ± 30 nm |
| Emitter | FP-LD |
| Connector | 2.5mm Universal (SC/FC/ST/LC) |
| Operating Modes | Continuous Wave (CW) and Pulsed |
| Weight | 150 g |
| Power Supply | 2 × AA batteries (not included) |
| Detection Range | Up to 30 km |
| Operating Temperature | -10°C to +50°C |
Selection Notes
Typically selected when you need a high-visibility 650nm VFL for fast field troubleshooting and lab checks, especially where mixed connector types are common and a rugged, carry-ready body helps with frequent handling.
May not be appropriate for workflows that require native LC/MU access without any adapters, or sites where visible-laser handling rules make open-beam fault tracing difficult to execute consistently.
Application Details

- Telecommunications Maintenance: Identifies fiber damage, poor splices, and connection issues quickly.
- Fiber Installation Testing: Ensures continuity and proper routing of fiber networks.
- Optical Engineering Applications: Useful for diagnostics in optical device production and research labs.
- Multi-Environment Use: Crash-proof and dust-proof design ensures performance in harsh conditions.
Packing List

- 1 × VFL Pen
- 1 × Carrying Pouch
- 1 × Lanyard
- 1 × User Guide
Tips for Use
- Remove the batteries when not in use to prevent leakage and oxidation.
- Keep fiber heads clean for optimal tester performance.
- For LC/MU connectors, a conversion adapter may be required (not included).
FAQ
Q1: What power levels are available?
Typically 10 mW, 20 mW, or higher depending on model.
Q2: What is the maximum detection distance?
Up to 30 km depending on output power and fiber condition.
Q3: What connectors are supported?
Universal 2.5mm ferrule; LC supported with adapter.
Q4: Is it suitable for APC connectors?
Yes, though reflectance may vary.
Q5: Does it have laser safety protection?
Yes, includes dust cap and safety lock functions.
Q6: What are the operation modes?
Continuous wave (CW) and pulse mode.
Q7: Is it field-durable?
Yes, made with reinforced metal housing for long-term use.








