2 Pack Single Mode LC 5dB Fiber Optic Attenuator SM Fixed LC/UPC in-Line Male to Female Fiber Attenuator M/F Single-mode Fixed SM 5dB,Blue Color. The optical attenuators mainly used in fiber optic to debug optical power performance & optical instrument calibration correction & fiber signal attenuation to ensure the optical power in a stable and desired level in the link without any changes on its original transmission wave. The optical attenuator is widely used in fiber optic communication systems, fiber optic CATV, high power optical device measurement Fiber Connector: LC/UPC Mold type:Single Mode Attenuator db:5dB Light weight, small volume, high accuracy, good stability and convenient operation.