Feature: 1. 20KM TESTING: This fiber visual fault locator has a longer penetration distance of 20KM, with stable performance, and long service life. 2. 2.5MM CONNECTOR: This visual fault locator uses a universal 2.5MM connector and supports common interfaces for FC, SC, and ST. 3. DETACHABLE DESIGN: The metal pen head of the fiber optic source tester is detachable, making it easy to replace the ceramic core. 4. WORK PRINCIPLE: The VFL pen is driven by constant current source and connected to the optical interface to enter multimode and single mode optical fibers, achieving fault detection function. 5. MULTI PURPOSE: This red light pen is an indispensable tool for fiber optic engineering construction, fiber optic network maintenance, and optical device production and research. Specification: Item Type: Fiber Optic Visual Fault Locator Material: ABS Output Distance: 20KM Wavelength: 650NM±10NM Fiber Optic Connector: Universal 2.5MM Connector Working Temperature: +10℃ to +45℃ Flashing Frequency: 1HZ Working Humidity: 30% to 90% Battery Type: AAA Battery x 2 (Not Included). Package List: 1 x Fiber Optic Visual Fault Locator1 x Storage Bag