[High Efficiency] Easy identification of fiber breakpoints, poor connections, bending, or cracking for locating the correct fiber to splice or quickly finding faults. The 30mW visual fault locator emits a 650nm bright red light for fiber tracing, fiber routing, and continuity checking. Breaks or faults in the fiber will refract the light, creating a visible glow around the affected area. [Functions] This fiber optic tester is ideal for field testing with multiple features including constant output power, multi-interface compatibility, low battery warning, long battery life, and long-distance detection. Super bright output powered by convenient AA batteries. [Widely Used] 2.5mm universal connector designed to be compatible with ST, SC, FC, and LC interfaces, fitting both round and square ferrules of various fiber optic cables. [Long Output Distance] The 30mW visual fault locator delivers strong output power, emitting a bright red light effective up to 20-30 kilometers. High-efficiency power circuit ensures stable performance. [Crash-proof and Dust-proof Design for Pen Head] Features a stainless steel tip and aluminum body for durability against impact and dust. Grounded case design helps prevent ESD damage. Batteries: Two 1.5V AA batteries (not included) Type: A Color: Green + Black Material: Aluminum alloy Package Contents: 1 x Fiber Identifier Note: Light and display differences may cause slight variations in color between the image and the actual item. Measurement error allowed is +/- 1-3 cm.