15-20km VFL Fibre Optic. Pen Visual Fault Locator 20mw Optical Tester Fibre Checker 20mw. 20mW(15-20km). The 650nm Pen-type Visual Fault Finder is specially designed for field personnel, engineers who need an efficient and economical tool for fibre tracing, fibre routing and continuity checking in an optical network during and after installation.
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