Features GOOD DETECTION PERFORMANCE: The detector has a longer penetration distance, stable performance, and long service life. EASY TO USE: Visual fault locator supports FC, SC, ST common interfaces, detachable metal pen heads, easy to replace ceramic cores. MAIN FUNCTION: Driven by a constant current source and connected to an optical interface, the tester enters multimode and single mode optical fibers to achieve fiber fault detection function. It is an indispensable tool for fiber engineering constructio 30KM MEASURE RANGE: This fiber tester has a 30km testing range, suitable for long distance test work, choose for more convenience! EASY CARRYING: With a storage bag, this VFL fiber tester can be easily carried to different scenes to use. Specification: Item Type: Visual Fault Locator Material: ABS Output Distance: Approx. 30000m / 98425.2ft Wavelength: 650NM ± 10NM Fiber Optic Connector: Universal 2.5MM connector Working Temperature:+10 ℃ to +45 ℃ Flashing Frequency: 1HZ Working Humidity: 30% to 90% Battery Type: AAA battery x 2 [shipped without battery] Package List:1 x Visual Fault Locator 1 x Storage Bag  Package List 1 x Visual Fault Locator 1 x Storage Bag