1Product Usage: The pen type visual fault locator is specifically designed and maintained for optical cables and circuits, locate defects on wires and cables, search for fiber breakage and equipment with defects in optical cables. 22.5mm Connector: This fiber optic tester has a 2.5mm universal connector designed specifically for ST, SC, FC, LC interference with circular and square shapes of different fiber optic cables, with a wide range of applications. 3Non Contact: This fiber optic test pen adopts a non contact connection, which does not damage the end of the fiber and transmitter, and the output power is not affected by voltage fluctuations, improving measurement efficiency. 4Aluminum Alloy Body: The fiber optic tester is made of aluminum alloy material, impact and oxidation resistance, has good dustproof effect. The grounding design of the shell effectively prevents damage. 5Wide Application: This visual fault locator is lightweight and portable, with stable output power. Suitable for CATV telecommunications engineering maintenance, comprehensive cabling system fiber optic engineering, optical measurement drive engineering, etc. 1 x Fiber Optic Test Pen 1 x Ceramic Core 1 x Storage Bag 1 x Lanyard 1 x User Manual