Visual Fault Locators (VFLs) use visible light to help technicians identify breaks, sharp bends, bad splices, and continuity problems along accessible portions of a fiber path. They are useful for quick field checks before deeper testing with an OTDR or optical power meter. Engineers should consider connector compatibility, operating mode, output class, battery requirements, and the type of faults expected in the deployment. ISP Supplies provides VFL tools for fiber installation, troubleshooting, and maintenance.