Function: 1. do fiber testing tool: specially designed do maintenance of cables and optical lines, this VFL pen can locate defects on cables, visually search for gaps in fibers. 2. Non-contact: Adopt non-contact connection way, no ma losses for fiber optic and transmitter face, and voltage fluctuations do not affect the output power. 3. Wide application: the universal interface 2,5 mm provides a wide range of applications, the output distance is do 60 km, which is very practical. 4. Stable output: this tester fiber optic source is energy efficient, can output power stably, is a good do fiber optic testing tool. 5. Easy to carry: tester fiber optic ma small size, is lightweight, comes with pen and lanyard cover, more convenient do carry. Specification: Item Type: Visual Damage Locator Material: Aluminum Universal interface: 2,5 mm (FC SC ST) Output wavelength: 650nm 10nm Optical Output Power: > 60MW Adapter of optical fiber: universal connector Output distance: 60 km Operating temperature: 0 do 60 Storage temperature: -20 do 70 Battery type: 2 AA 1,5 V batteries (supplied without battery) List of packages: 1 x Visual Damage Locator 1 x Pen Bag 1 x Lanyard 1 x Manual Note: Don't aim for the eyes. Install with 2 pieces of AA batteries to use directly.