1. High-precision measurement - the 20km optical cable tester can quickly measure parameters such as optical fiber optical power, optical loss, and field strength, with high measurement accuracy and reliability, so users can more accurately understand the use of optical cables. 2. Rechargeable and low power consumption - the instrument uses a rechargeable design, and it can be used continuously for more than ten hours after being fully charged. At the same time, it also uses low power consumption control technology to reduce battery energy consumption and extend battery life. 3. Pen type design - the visual fault locator adopts a pen type design, which is easy for users to carry and use, and the operation is simple and fast. 4. Reliable performance - the test instrument is made of high-quality materials, has strong anti-interference ability and stability, so it can be applied to optical cable testing and fault location in various environments. 5. A variety of test modes - the optical cable tester can provide a variety of different test modes, such as clock test, continuous wave test, observation mode, etc., which can meet the different test needs of users and is convenient and practical.