1Anti Static: Fiber optic visual fault locator adopts nanotechnology, multiple electrostatic protection, with optical port protection device. 2Fault Detection: Fiber light tester is connected to the optical interface and can be used to detect fiber faults when single mode or multi mode fiber is inserted. 3Three Modes: Fiber optic power meter has three working modes: constant light, fast flash, slow flash, and constant power output. 4Pen Shaped Design: The visual fault locator adopts a pen shaped design, which is easy to use and carry, and is coupled by optical fiber to ensure optical power. 5Aluminum Alloy Shell: Fiber fault locator shell is made of aluminum alloy, which is sturdy and durable. It is driven by a constant current source and can emit a red light. Item Type: Fiber Optic Visual Fault Locator Material: Aluminum Alloy Shell Model: VFL650 2S Transmitter Type: FP LD Optical Connector: 2.5mm Universal Connector Working Mode: CW and Pulse (3Hz and 9Hz) Pulse Frequency: 3Hz to 9Hz Operating Temperature: -20C to 60C Storage Temperature: -40C to 85C Battery: 2 AA Batteries (not Included) 1 x FiberOpticVisualFaultLocator 1 x User Manual 1 x Storage Bag s without battery.