Feature: 1. PORTABLE DESIGN: Visual fault tester, portable design, light and practical, easy to operate and carry, is a common tool for optical fiber testing. 2. MAIN PURPOSE: Specially designed for maintaining optical cables and lines, used to locate cables and detect whether optical cables are defective. 3. CONTACTLESS CONNECTION: The end faces of optical fiber and transmitter are not damaged, and the output power is not affected by voltage fluctuation. 4. WORKING RANGE: The output wavelength of the red light test pen is 650nm ± 10nm, with stable output power and wide application range. 5. ALUMINUM ALLOY: The pen shell is made of aluminum alloy, which is corrosion and abrasion resistant, and can be used in various environments. Specification: Item Type: Visual Fault Locator Model: HT 50 Material: Aluminum Alloy Output Wavelength: 650nm±10nm Optical Fiber Adapter: Universal Connector Output Distance: Approx. 50KM / 164042ft Operating Temperature: 0-60℃ Storage Temperature: -20-70℃ Battery Type: 2 x 1.5V AA battery(not included battery). Package List: 1 x Red Light Pen1 x Pen Bag1 x Lanyard1 x Use Manual Note: Do not aim at the eyes.